131 " 132 TWO PHOTON COHEHENCE in NUCLEAR MAGNETIC RESONANCE* Fourier Transform Multiple Quantum HMR E.L

131 " 132 TWO PHOTON COHEHENCE IN NUCLEAR MAGNETIC RESONANCE* Fourier Transform Multiple Quantum HMR E.L. HAHH and D.Q. GOLD, Department of Physics, University Alex Tine* or California, Berkeley, California ?H720, USA University of California, Berkeley

23 Sodium (Ha ) nuclei In & single crystal of NaNO3 provide a four level system with three unequally spaced transitions. • The In Fourier Transform Multiple Quantum HKR1 multiple quantum system is examined with radio frequency pulses Intense enough to transitions in a coupled spin ayaLem are excited and detected in excite .two and three photon transitions. Solutions which describe the two-photon precession exactly Including the effects mich a way that a specific n-quaotum spectrum can be obtained for of off-resonant single photon transitions are verified for each n where n - 0, 1, .... N (N - number of coupled apln-4 nuclelj. fL T,,T2- **• Consideration of the effects of non-negligible T2 and Several of ot-r recent developments and applications In this area will considerations pertinent to the fourth level are examined. Two photon analogs of familiar single photon effects are considered be selected for discussion from amongst the following: theoretically in the absence of damping and In a solid. Obser- 1. Simplification of spectra allowing -ipalysis; vations of the two photon analog of the well known single photon 2. Tine dependent non-linear coherence processes; effects of rotary saturation after spin locking and adlabatlc fast passage are demonstrated for the, MaNO, system, Modifica- 3. Stochastic multiple quantum processes and n-quantum tions of these two photon effects due to single photon reso- distribution; nances are discussed. The complete four level system Is exa- 4. Multiple quantum relaxation and extraction of correlations; mined after Irradiation with intense rf for times longer than T2 but much shorter than ?,. A theory is proposed that gives an 5. Study of structure and dynamics of oriented molecules exact three level solution in a solid for tbe experimental con- without deuterium labeling; dition mentioned above- Adlabatlc fast passage results are 6. Multiple quantum double reaanance; calculated that apply to solids and compared with the adlabatlc fast passage experimental results. For intense Irradiation 7. Relationship to optical coherence work. I three photon spectra are observed that occur simultaneously with a single photon transition. Power dependences of the simultaneous three photon and single photon resonances have been measured. S. Vi !gn, T. W. Shattuck and A. Pines, Fourier Transform Double-QuanLum HHR ,n Solids. Fhys. Rev. Letters, 22* A3 (1976). A. P:.nes, D. Vemmer, J. Tang and S. Simon, The 5- and 6-Quantuo KMH 'Supported by the U.J. National Science Foundation. Spei ra of Oriented Benzene, presented at the 1978 APS Meeting, 'ranciaca. Bull. Am. Phya. Soc, 13, 21 (1978).

133 A CIDKP APPROACH TO SICKAL EHRAHCEHERT IN MAGNETIC ftESOKANCE REACTION YIELD DETECTED MAGNETIC RESONANCE OF INTERMEDIATE COMPLEXES I Joachim Barnon IBM Eesearch Laboracory, San Jose, California 95193, 'JSA E.L.FRANKEVICH, V.I.LESIM, A.I.PRISTUPA, I.A.SOKOLIK, M.H.TRIBSL Institute of Chemical Physics, Moscow 117334, USSR

Chaaically induced Magnetic polarization (CXHP) can be achieved via There arc many condensed phase reactions whose rates depend different procaaaea vheraby short lived paramagnetic internediates In liquids on the spin of the intermediate complex (IC) fonnea during the lead to nonequlllbrlum population* of the nuclear apin elate* (C1DHP) of the collision of reacting particles. They are for examples the tri- diaasgnetlc producta or of tha starting Material*, and to similar anoaalies in plet excitons annihilation T+T-^S* (1), triplet exeltons quench-

the electron apin atata population (CUtEP) of the paramagnetic intermediates. ing by radicals T+R^S+R (21 ( recombination of free radicals Tha latter can either be free radical* or triplet states, and they are most R +R.*1 (R R_) (3) in molecular crystals. As for IC life times are conveniently generated by photoexcltatlon. For this, purpoae little or no shorter than the spin-relaxation time T.| ,the reactions products modification of etandard Magnetic reaonanca spectrometers are necessary* The are formed from the singlet containing levels for reactions (11 two principal mechanism* which generate CDtP. namely the Radical Fair Hechaniaai and (3) and dublet containing, levels for (2). The IC spin state and th* Triplet Ovexhaoaer Hechaniaai, will be outlined. Vhereae tbe latter can be altered by static magnetic fields. Authors have shown reqolzaa only phocophysical excitation of a suited reagent *nd oo chemical that resonance microwave power induces resonant transitions be- change, the Hadlcal Pair Hechanisai typically involvea chemical changes. Bow- tween Zeeoan levels of IC giving rise to a change in the popu- aver, by taking advantage of reversible chemical reacitone, the Radical Fair " lation of the singlet and dublet containing levels. The transi- Hechaniaai can also be used for aignal enhancement without causing unreasonable tions were experimentally revealed as the REACTION YIELD DETECTED complications In tbe spectra. Its application allova one to selectively en- MAGNETIC RESONANCE (RXDHR) spectra of IC. KY.DMR method gives in- hance the aignal* of specific daasea of aDlaculea as well as of selected formation on the nature of ICs and on their life times. By groups of nuclei. Tbe enhancements can Be either positive (absorption) or studying the annihilation (1) of polarized triplet excitons in negative (eadaaion), and from tbe enhancement pattern* tbe absolute sign of anthracene-tetracyanbenzece the transitions have been discovered the spin coupling conataaca may be determined. A variety of reagent* will be caused by the absorbance of one and two microwave quanta by IC, discussed, which allow specific signal ennatn-a—nt of auch diverse substrates having life time of 1.4«1O~ s. RYDMR spectra for the reaction at amlou, alcohol*, aromatic compounds, iona, Ic* tones, olefins, and sllanea. (2) have been obtained by studying a delayed fluorescence of TU OvmxhaiuMr Triplet Bachanlam on the other hand aay be u*ed either intra- anthracene-dimethylpyrcaelXitlmide in reaction (!) whan triplet or lnteraolsculaxly. la the latter, caae It la even poaaihle to enhance the excitons life time was determined by quenching by radicals. The aignal* of chemically very different solute molecules simultaneously. IC life time for reaction (2) was equal to 6*1O~9 a. RY.DHR Then CUP provide* a powerful alternative to other known method* for spectra for reaction (3) have been detected on changes of the aignal. enhancement in magnetic reaonanca, but its •uccauful application re- photoconductivity caused by the dissociation of ion-radicals in quires some basic uadef*tendlng of both the pbyaics and tbe chemistry upon tmtracene and anthracene*

A.V.DUSHKTJf, Yu.A.GRISHIlf, I>«M~«1EXHEBt Institute of Chemical Kino tics and Combustion) Soviet Academy of Sciences, Siberian Branch, Hovoaibirek 630090 ,UESH

Novel phenomena associated with electron and nuclear spin effacto on chemical radical reactions are reported* "Theoretical and experimental investlgationa made in this field in the Institute of Chemical Kinetics and Combustion (fTovosibirslCi USSR) are reviewed in detail. Data on Jne influence of a per- manent magnetic field on chemical reactions as well as on bio- chemical processes are reported. The theory presented la based on, the influence of & magnetic field on the intersystem croaaing in a pair of paramagnetic particles - the reaction product precursors* Magnetic fields can effect the reaction rate since not all spin states of the pair axe reactive. A "spin forbidden" process may be permitted bfr magnetic interactions in the pair. The theory considered is illustrated by a number of experimental results dealing with, uagnetlc field effects on the reactions of elementoorganio compounds and ensymic ox-red reactions. A novel.- lectopic effect in the radical reaction kinetics- magnetic isotopic effect - is considered which is associated with the Influence of hyperfine interactions on the radical recombination probability* Experimental results on magnetic iaotopic effects are presented, and optimal conditions for observation of magnetic effects are discussed. Experimental results on chemically induced dynamic nuclear polarisation in low magnetic fielda are summarized. A method for direct observation of the low field GIDNP has been developed* A. novel technique for measurements of CHIHP enhancement factors in low magnetic fields in photochemical reactions is proposed, ibis technique includes pulse Irradiation and fast registration of BUR signals in low fields. CIDHP enhancement factors in Uradlcals have been measured during cyclododacanone and cyclohexanone diperoxtde photolysis. A312 A3U, CIDEP JttID CIDNP IN RADIATION CHEMISTPY. CUMP AND GIDEP HI LOT UAGHETIC FTKTflTfi POLARIZATION TRANSFER BETWEEN ELECTRON AND NUCLEAR SPIN SYSTEMS" IC.M.SAEIKEOV', Institute of Chemical Kinetics ond A. D. TRIFUHAC, Chemistry Division, Argonne National Combustion, the USSR Academy of Sciences, Siberian Laboratory. Argonne, Illinois 60439 USA Branca, Novosibirsk 620090, USSR Parallel study of CIDEP and CIDNP in radiation chemistry has The chemical polarization of nuclear spins in radical re- allowed observation of a straightforward example of polarization coabination products and. the spin polarization of unpaired, transfer between electron and nuclear spin systems by electron- radical electrons have been calculated for short-lived radical • nuclear cross relaxation. While this OverhauBer CIDNP can be ob- pairs with, any number of magnetic nuclei using the projection served in many related systems, we will discuss the aqueous operator technique developed by us« The principles of CIDNP and acetate radiolysis, since we have made extensive study of both CIDEP in low magnetic fields have been formulated for short- - CIDEP and CIDNP in this system. The experiment is schematically lived radical pairs. The situation when a radical pair turns in- outlined as follows: to another one due to reactions is also considered* Rec.cur.on1; C1CH2CO relations connecting the polarization in a given pair with that •CH,CO,<*)- aq m in the preceding one have been obtained for successive pairs. CIDEP For example, the analysis of the OIDUP effects far a- one-proton radical pair shows that in low magnetic fields, like in high Dissociative electron capture by haloacetatea yields the acetate fields, the radicals of the pair are polarized with opposite radical: in turn, this radical can undergo bimolecular reaction N^igns. However, in contrast to the case of high fields, in low yielding succinate. The hydrated electron can be prepared with fields the electron polarization of that radical possessing a its electron spin polarization in emission (+) as shown by the magnetic nucleus exceeds the polarization of ito partner by a CIDEP observed using time-resolved EPR. The electron spin polar- factor of 5» THa sign, of the mmuf effect for this system ia in- ization is transferred tti the acetate radical (*> (CinEP observed dependent of that of the hyperfine interaction constant. by time-resolved EPR) and subsequently the nuclear spin of the The spin polarization has been analyzed for the simplest (diamagnetic) product succinate can be observed in emission (+) radical pairs with one and two magnetic nuclei taking into ac- as well (CIDNP using FTNMR). We will discuss each of these steps count the contribution of all repeated radical contacts at the in tuii- reaction The Overhauser CIDNP effect has received much attention since it was the basis for the first explanation of the CIDNP phenom-

Buchachenko,A.L.t Sagdeev.R.Z. and Salikhov.K.U. magnetic and enon. Over the years there has been much speculation as to spin effects in chemical reactions, "Nauka", Novosibirsfc, 1978, whether Overhauser CIDNP contributes to CIDNP in some systems. p.298- The only systems studied to date involve transfer of "triplet" electron polarization in photolysis.

•Work performed under the auspice* of the Division of Basic Energy Sciences of the D. S. Department of Energy.

A 313 A3M

MAGNETIC ISOTOPE ENRICHMENT AS A RESULT OF MAGNETIC THB EFFECT OF ELECTRON RELAXATION ON C'iEMICALLT INDUCED INTERACTIONS IN THE RADICAL PAIRS DYNAMIC NUCLEAR POLARIZATION A.D.PERSHIH. A.L.BUCHACHENKO, Institute of Chemical Physics, Yu.A.GEISHIB, A.V.PUSHKIN. T.V.DESHINA., Yu.H.MDLIS and Academy of Sciences of the USSR, Moscow 117334, USSR H.Z.SAGDEgy, Institute of Chemical Kinetics and Combustion, the Soviet Academy of Sciences, Siberian Branch, Novosibirsk Honequilibrium distribution of C isotope among the products 630090, USSR of radical reactions was observed /I/. This phenomenon is a result E.KAFTSHI, Deportment of Physical Chemistry, University of singlet-triplet transitions in the radical pairs induced by Zeeroan and hyperfine magnetic Interaction!1. The nuclear spln-de- of Groningert, Groningen, the Netherlands pendent rate of singlet-triplet transitions and, thus, the nuclear spin-dependent rate of radical pair recombination, leads to The first experimental examples of -the CXDNF- sign, inver- enrichment of magnetic isotopes in the recombination products sion in geminate radical pairs (the so-called F*-paixa) have been (if the precursor is a triplet radical pair) or in the escape obtained. This inversion is possible Ouring Hf -Hg—^-flJj- *B£ products (provided that the precursor is a singlet pair). The radical pair transformation if the electron relaxation time theory of this phenomenon /2/ is similar to the CIDNP theory. The of one of the radicals (or both) of the initial HP is shorter dependence of the recombination rate on the nuclear spin is the than the time of singlet-triplet evolution- Fast electron remagnetic isotope effect. The enrichment of the13 C isotope induced laxation in the radicals of this pair results in the same by this effect in the products of photochemical decomposition of CIDNP sign in the geminate recombination products of the se- dlbenzyl ketone, thermal decomposition of benzoyl peroxide, and condary pair bath, for singlet end' triplet precursors. other reactions was shown to depend on the hyperfine coupling The effects predicted have been verified, experimentally constants and magnetic field strength. for 1H and 1'c CHWP in the reactions of dicumyl peroxide The properties of magnetic isotope effect that differ from thermolysis and cyclohexanone diperorJ.de photolysis. The for- the classical isotope effect are discussed. mer reaction proceeds through diffusions! F* pairs, the latter through F" biradicals.

1. Buchachenxo,A.L.r Galimov,E.H., Ershov,V.V., Nikiforov,G.A. and Per shin, A. D. Doklady AN BSSR 22B, 379 (1976). 2. Buchachenko.A.L. uspekhl Khimii 45, 761 (1976).

v A322 er OOOBCTIOI mcmm on *o US BSBUOB BUR ^Bl 1BD STJUJEIC BUCUIB FOT^BIZ&TIOV IBSDCED xrauencnr WITH EOUS n now DORS J-HB snnoomuoTORs BT OfflCIL WUylMfi IB COlCIBSaSBZ) SHXC0H* A.u.AROIOV, O.E.jntBS, Y.I,3A»AB0V. V.I.SAKHAROV, A.H.TITKOV T.TH.wTjninBro. g.T.BaGaAIV and BU.ZHHBIKOT, A.F.Ioffe Phrsico- A.r.Ioffe Phyoical-Tectmlaal Institute of the Academy of Scian- Teciaic*! laitltnte, VBBB lesdear of Soloaora, Xaningrad 1940211 oe* of the USSR, Leningrad 194021, TOSH. We have studied the behaviour of optical polarisation of The advent of optical pumping technique, i.e. the photo- ^Sl nuclei In silicon containing both deep sad shallow impuri- axcitation of ep±= polarised electrons with circularlly pola- ties, as a function of the weak magnetic field used In optical rized light, oade accessible the study of spin relaxation in pumping, and recorded the dynamic polarisation Induced by opti- systems, where the conventional BSP technique cannot he applied. cal pumping via the increase la the mat-signal. The addition of In particular, optical pumping makes possible the measurements gold to phosphorus-doped silicon la shown to raise the degree of of spin relaxation Maes T (is short as 10~10 - 10"1V) of s nuclear polarisation which appears two orders of magnitude larger photoelectrona in highly doped p-type semiconductors /1/. As for 81 as compared to 81 , due to the absence of It «BS shorn theoretically /2/, a new mechanism should govern thftrmM electrons in the conduction band end the reduced photo- the conduction electron spin relaxation (CSSR) in such a syB- excited electron lifetimes. Moreover, the gold sdded to t«m: namely the exchange interaction between photoeleetrons and majority holes. P/P silicon ham been found to be responsible for the de- We present the results of systematic measurements of "T n ' '•mi s pendence of tiie degree P in p-type GaAa and GaSb, doped with acceptor impurities in n and direction of nuclear concentration range 1017- 1020om"-'. The analysis of Tj as polarisation induced by function of doping level and temperature has shown, that the circularly polarized light exchange Interaction with holes ie the dominant mechanism of on the stxength of the CSSR In studied range of doping and temperatures. magnetic field H (sse Fi- The new phenomenon - enhancement of CESR rate bv elastic o gure)* The variation of P with pumping light intenaltr under deformation of the crystal has heen observed. The effect was n B of variable strength has also been investigated. We will pro- shown to be due to quenching of hole spin relaxation in Q pose a model Telating- the optical polarisation in silicon con- deformed crystals caused by the change of valence sand taining gold and phoaphorus atoms to contact and dipole-dlpole structure. interactions of nuclei with electrons trapped by phosphorus atoms and those looallzed to deep levels in gold, respectively. 1. Garbuzov, D.Z., Ekimov, A.I., Safarov, V.I. Zh.Eksp.Teor. The dependence (shown by full curve in the Figure) of the degree Fiz. Pia"ma Red. 1J. 36 (1971) /JEEP Lett, ij, 24, (1971)/ of optical polarization on Ho, derived from the theoretical con- 2. Bir, G.L., Aronov, A.G., Plfcus, G.E. Zh.Eks.Teor.Piz. 6JJ, sideration of nuclear Interactions as a function of a weak mag- 1382,(1975) /Sov.Ihys.-JEEP $2. 705 (1976)/ netic field, will be discussed.

A323 ELECTBOH SPOT HELAIATIOtT DDE TO EEECTRON-HGLE EKHAHGE IHTERACTIOH AS A HECHAHISH OF HOH-3JUILIBHIH1I ORIEBTATIOH OF ELBCTHCPS HI ELECTROS-HOLS DROSS (EHD) HI SILICON IK EUtxHSdC "ST w.j JI P.D.ALTOHHOV, G.E.PICUS, A.A.HOGACHHT A.F.Ioffe Pbysico-Teebnical Institute, Academy of Sciences of the USSR, Leningrad

Anomalously high magnetic-field-induced circular polarization of electron-hole drops C3S) luminescence was observed. The sign of EHD luminescence polarization was found- to be opposite to that of the free excitona implying that the polarization of BSD luminescence is mainly due to the electron spin orientation. The nmrlimirc value of the electron polarization was as higu as 0.5 in the magnetic field of 5 Tesla while the calculated equilibrium polarization should be by more than an order of magnitude smaller. The polarization was stronger at the high energy side of the BSD line and appeared to be proportional to the ratio of the intensities of the free exciton and BSD lines. The results show that the polarization of the BSD luminescence is due to non-equilibrium, electron orientation resulting from free excitons condensed in drops. Under high excitation the time of condensation becomes snorter and the electron spins in exeitons have no time to be oriented which leads to a decrease of polarization of the 5HD luminescence. The electron spin re- ' lsxation time in excitons wss 10"3aec while for the EHD it was by an order of magnitude greater. The theoretical investigation shows that the only feasible mechanism of the spin relaxation giving such a difference in the electron spin relaxation time for free excitons and EHD is the electron-hole exchange. The electron-hole exchange interaction constant for 81 was estima-

ted as £te =10"* * terser. Bon-equilibrium electron orientation in BSD must lead to a strong nuclear spin orientation which may be observed in HHR experiments. A 3301, A 3302 TRIPLET BXCITON DYNAMICS ON TCB BY PROTON SPIN RELAXATION OPTICALLY DETECTED WGNFTIC RESONANCE OF THE TRIPLET

j.u. VON sctmrt, H. ,< cKr w. GUTTLER AND H.C, HOLP STATE OF PHEOPtftTINS • Physikaliaches institut, Teil 3, UniveraitHt Stuttgart, Germany T.J. SCHAAFSMA. AND S.J. VAN DER BENT, Laboratory of Molecular Physics, I The increase of the proton spin relaxation rates by optically exci- Agricultural University, De Dreyen 6, Kageningen, The Netherlands. ted triplet states in molecular crystals is demonstrated on 1,2,4, S-Tetrachlorobenzene (TCB). The crystal structure of TCB favors a The triplet state of pheophytin-a, derived from chlorophyll-a by one dimensional exciton motion which is expected to be coherent at substituting Mg by two protons, has been detected using magnetic resonance in low temperatures. This exciton migration modulates the hyperfine in- zero magnetic field COO*)," monitoring its fluorescence. Fluorescence emission teraction to the nuclear spins 3C= SAI »f(t), and give riee there- of pheophytin-a dissolved in a n-alkane with a small amount of polar solvent fore to a proton spin relaxation according to added, contains several bands, originating from.differently solvated species. ••% Two zero-field transitions are detected at ID+Et and-ID-El Mlz, the frequencies z and relative amplitudes of the observed resonances depending on the A . J£x( us - Wz) (1) fluorescence detection wavelength. This provides a method for decomposing for a scalar interaction. J_. {bi) represents the spectral distribu- fluorescenccbands, as are often observed in tftuo, into separate bands for each tion of the hypecfine fluctuations, which are strongly dependent on species present, by reversing the OEM technique, i.e. observing the the kind of exciton motion. fluorescence emission modulated by microwaves resonant with a particular zero- Our NHR-results, obtained in a large temperature and magnetic field field transition, as is demonstrated far pheophytin-a and similar to a range, are compared with intensity spectra calculated theoretically technique developed by El Saved et al. /I/. The observed phenomena can be t [1] indluding the fine structure splittings which shift the transi- explained by a model involving zero-field spinVI ait ice relaxation rates to be tion frequency us at a given field strength in an ingle dependent dependent on the solute environment /2/. manner. Different models for exciton motion are confronted with the f experimental results for only one temperature (4.2K) in the figure 1. El Sayeii, H.A., Tinti. P.S., Owns, D.V., Cheai. Phys. Lett. 6, 395 (1970). below. 2. Van der Bent, S.J., Thesis, Wageningen, 1977. ft Fiq-1 Magnetic field dependence of the light induced proton spin relaxation rate Ti^l at 4.2 K. the broken and continuous lines are fitted curves using the intensity spectra calculated in Ref.1 and the parameters given in the- drawing. Only incoherent one dimensional exciton dynamics could be detected at and above this temperature in TCB. B./HG [i] H.Haken and E.Schwarzer, Chem.Phys.Letters 27, (1974) 41 r

ft 3303 A33CW \> FLUORESCENCE-DETECTED HICROWAVE RESONANCE SPECTRA STRUCTURAL FEATURES OF CHLOROPHYLL COMPLEXES III VITRO ABO OF CHLOROPHYLL ADD PROTOCilLOROPIIYLL JH VIVO AS UETERIIIIIED BY TRIPLET STATE ODMR UNDER LASER EXCITATION R.H. Clarke. D.R. Hobart, H.R. Leenstra and P. Hitra, Departrent of B.AVARHAA and A.SUI5ALU, Institute of Physics of the Chentstry, Boston University, Boston, HA 0Z215, USA. Estonian S5R Academy of sciences. Tartu 202400, USSR We have used the properties of the photoexdted triplet state as a structural probe Into t le makeup of chlorophyll aggregates. By measuring the - It is shown that fluorescence-detected microwave resonance zero-field optiwilj detected magnetic resonance (ODMR) transitions In the (FDHR) Bignals can.be essentially increased by using cw laser excited triplet stal^ for interacting chlorophyll systems and comparing these excitation which produces high triplet state populations. FDHR results with those foe the monomer, a description of the geometrical features spectra of chlorophyll a (Chi a) and protochlorophyll (Protochl) of the chlorophyll aggregate may be obtained. The systems to be described in ether solution at 4.2 K are obtained using 632B & and 1416 A -Include chlorophylls In hydrocarbon solutions, covalently linked chlorophylls, laser radiations, respectively. Monitoring on one of the sharp chlorophyU-protein complexes and reaction center chlorophylls. Zero-field lines (6748 A) occurring in the fluorescence spectrum of Chi a optically detected EPR and ENDOR will be presented for these systems and dis- under monochrcaatic excitation rather distinct FDHR spectrum is cussed in terms of the current models for the chlorophyll aggregate structure observed: a splitting of the 950 MHz peak and its weak sattellite in vivo. are found. For the first tine, the FDHR spectrum of Protochl is observed including two main resonance lines: 955 and 1175 MHI, the former having an amplitude up to 25% of fluorescence intensity change. The resulting zero field triplet state splitting parameters are D = 0.0355 and E = 0.0036 an"1. Both FDHR lines of frotochl, as .well as of Chi a correspond to a decrease in fluorescence intensity. Consequently, the most %'• long-lived z-sublevel of the 1^ state connected via the D + E and 4- D - E magnetic resonances with the short-lived x- and y-levels has the lowest steady-state population. As compared with Chi o. the D-value and the triplet state life-time are increased in Protochl due to the absence of additional protonation of the 7-8 double bond. is . A 3305 A'3306 H1OTOCO1IDUCTIVITY DETECTED UAGIETIU RiSBOHAHOB OP SIIORT-IIVBD ESB I.IHE SHJVPE OP TRIPLET EXCITONS IN MOLECULE PAIRS IHTEIUffiDIATE CT-3TATES IH MOLECULAR CRYSTALS f- REIKEKU, MateUUng «lr Theor. Phyeik I. OnlversitHt Ota K.M.Tribel*. I.A.SoKolifc, A.I.Priatupn, E.L.?rankevich 79OO Ulm, Germany Institute of Chemical Physics of the Academy of Sciences of the USSR, Moscow 117334, U.S.3.R. Tht ISs line »najse at triplet excltons, which move In a coupled '.'he work reported is an original application of the method . cohferent (tnd incoherent manner within pairs of differently orien- of the RXDUR (Reaction Yield Detected Magnetic Resonance /1/) to tid ilouciilej, Is calculated exactly /I/. The model Hamlltonlan study intermediate exciteu ntatea in molecular crystals uelsg the (tll> b + S+b h photoconductivity. External static nagnetfc fields are known to , !>„„• n n- "- 1 t ST,-S+b*b2S.V change the photoconductivity of molecular crystals. This is associated with the fact that the magnetic field mixes intermediate CT singlet and triplet excited states. The process of charge carri- rators for- an et«ctron-hole pair at site i): the first one descri- Si: era generation consists In the dissociation of the excited CT- » bes the coherent potion of the excitons; the influence of vibra- atatea producing free holes and electrons localized on acceptor '*" tions IB taxen Lnto account stochastically by local (n=n*) and 1 molecules. Hence the variations in the photoconductivity when noa-lqcal (n-n'l fluctuations /2/ in the second term; the spin Imposing the external magnetic field reflect tl,o variations of par-t of the llamj_ltopian contains the Zeeman et.tjrgy and the fine I the total concentration of the structure terms of the two differently oriented molecules. In the intormediute excited CT-Btates completely coheirent case (very low temperature, fluctuations ne- of both multiplicities. One gligible the line positions of ESR transitions between" stationa- might expect that magnetic ry states, in the low&r Davydov-component and of corresponding resonant transitions between tra.nsitlc.ns in fche upper component are slightly different. With

_ f , ,. iiseman aublevels of the excited increasing temperature the excitation is scattered fay the fluctu- » L ^* triplet CT-stEtes T+1 and the ations between the states of the upper and the lower Davydov-eom- l triplet CT-3tate Io mixed with singlet OT-state S also could porients tes-iltitig in a narrowing of the ESR line At high enough cause a variation of the photoconductivity, if the lifetimes of temperatixrea (strong fluctuations) the exciton motion is incohe- (S-T,,) and T^-states are different. rent afld -the ESu line depends on whether the local or the non- In tho present work the magnetic resonant modulation of the local fluctuations Predominate In the first case the ESB-spec- photoconductivity of polyorystalline samples of molecular crystal! trum is oletennisicd by the lines of che isolated, differently waa observed for the first time. The magnetic resonance spectra oriented molecujea, vhereas in the second case again a narrowing of the triplet CT-state has been observed at room temperature. The occurs, now, horwever, by a hopping of the excitation between the typical spectrum of anthracene-tetracyanbenzene CT-crystal is two diUerently- oriented molecules. In the case of intermediate presented'ln the Pig. The life-time of the triplet CT-state, was starength of the fluctuations, the ESR line shape is more compli- shown to be about 10™° s.The concentration of the CT triplet cated sn<3. a detailed discussion also of this situation will be states measured, was about W5 apina per aample. Switching on the presentea. resonant microwave power decreased the photoconductivity.A scheme '. Reinelcer, p- FHys. Rev. B, in press. of the process of electronic excitation energy conversion is 2. Hakfli, H. an-d Str^bi, G- int The Triplet State, ed. Zahlan, proposed. A.fl,, Cambridge Onlvarsity Press. London, 1967. I.fcankevich B.L.,Pristupa A.I.,Leain V.I.,Chem.Phys.lett.47Cl977) 2.Rusin B.A..Prankevich E.L., phys.stat.sol. _3j(1969) 385.

A 3307 A 3308 T C0HSTRUCTIOK OF SPU-HAMILTOSIIH AID ETUUHOK OPUS PlHiMETEHS sPD. -3Bm0K ssLtjaiias m BICITKD TRIPLET M.MBSTKHKIB. G.WHYMAH, G.KLMKO and V.P0LIAYEI3, Institute STATE OF CHTSTA1MSB BSIZIL or Phyoiâl Qrgiinic and Coal Cbeaiatrr of tne Ukrainian A..A,Av-a«n*o « V.&.KatacheTteeT end S.H.FalculoT, Fhyaleo- Aeadeay of Seieneea, Donatak 340048, U33H T«ctmi.c8l Institute of X*o* TeoperafcureB at the Aeademy o* 8ttence» of the UlcralnUn SSB, Kharkov JI0I64, DSSH It la ahenm that the perturbation ttnory traatnent of Breitfa relatlTlatle eorraetioiia na^ ba goserallj radueed to tba Spin-Ha- To obtain the tenperatufe dependence of electron apln-lattiee •Utonlan oatbod aran though tba texaa of dlffarant aplna antar • i (Sift) rsi=e consêota hetaeen spin sublevela of tne ware function. Thia glTea a solution of tb« probltm dlacnaaad In eoiclted triplet state in the zero Sleid.oen- /I/, tha Spln-Haalltonlan la obtainad In atandard . {b»x>ho(eaceii« decay «as studied, is the condltlona of non- 3 («) . 0,I,2iJw|*u> ). Th« paraaatara DJ^ ara tha Intagrala of spira elienaeafc induced by toe puXae optical pumping •claan;' a two-particle danaltj matrix conponentB and of tranaltl- Ttie decay cutve auelyala *ea cerried oirfc oy tba reala- s oa apin danaltj aatrleaa C for tba rlxat-order asd aaeond-ordar eulogue wbicb baa been earlier used for the ana- costrlbutlona, raapaetlTaly), and alao of tba apberical tanaorlal lj-ala 'f pM>to<-jcit»jiJ BSR aignal ferns /3,i/ • In tbe rsnge of oparstora. Tha lattar ara eonatruetad from apatlal factors of tbi f~*O t He- riceseled to aeasure tao individual SIS race constants perturbation by nalng tba rulea aa thoaa formulate 1 In /Z/ •tioae Cemperstore depenianees approiinete »ell b; tite sun of tao for coaatruotlon of Irreducible tanaors T^frorn tba eoaponanta of ^frsnsl Linear In T ejnd dap«Dden.t: on T^ or T . The processes of the apin rector. Tha two- and one-particle apin danaitlaa aenti- sp>lo-;honon reXaxitlon in crystalline- tenayl CCgH^COCOCgEe) are oned ara expreeaed through tha ioek asnj-alaetron coordinate »a- caxBidtred froai tbe point of 'ten of aelf-trspping of electronic Va function. A jsrturbation linear Inapin, a.g. the apln-orbltal due to confomatlonal cbangea In molecules after pho- one, leada tr tha aaaw apin tanaon Ti) in tha aaoond order ae I tboaa Introduced hy tba twe-partlelo (apln-apln) perturbation la tha flrat. 3M "fourth powar of op in frequently included In tba tb Spln-Haailtanlan aaj appear only in tha fourth order of one-par- I. Varte-et P.J.?. Etoc. XIX Congress Aspere, Heidelberg, 1976, ticle perturbationa or in tha aaooad order of two-particle anaa. p- 109 The tan Jf«S phenoaenologioally introduced by Dllaloohinaki 2- Avdeeaaili A.J(., Eanonenko A.I., fakulov S.S. Itr.Acad.Nauk ariaea (atlO • I) in the aaoond order, already from tha one-par- SSSR, ««,. riE,, «a, 505 (IJBI ticle apln-orbltal interaction. In apite of ita absence In the )• v«0 4erBen-t S.J., it Jeg*r 1., Ecbatfaaa T.j. Rev. Sci. initial Brait Haailtonlan. luaarlcal apln-eitended Hartrea-¥ock Ittatim.. 47i 31.' C1976) (EH?) calculationa of ITS paraaeteraDj have been performed for "> Pellt C.C., Kin Soon Saa, Weisaasnii S.I. Cban. Phys. Letters triangulene (a • I), phenyloBaCbU)pnanyl«athjrlena (a • 2), and 'S, 29 CX978) for triplet atataa of naphthalene, anthracene, phenanthrane,and pyrene. lha agreement »ith erperiaent la reaaonable. The EH? al- way« gi™» &?- 0 in contraat uith the unreatrieted Uartrae - rock method, aa tne general theory raquiraa for radlcala la=^)- , 1. •cVeeny.B., Sttteliffe.B.T. Methoda of Molecular Quantim He - chanica, Acadeale Preea, London and lew York, 1969* Z. Ihynan.O., lusanoT.A., Meatechkln.lt. Iaor.»at.Wi. 28,65 C1976>). A3309. A 3310 J nuBiziiiOH or I3o AID % n HOTOKBMHWS " C- CIDHP Inveatliâtion of Photoinitlatora and Photoinduced Polvmerigatlon. or poBiuaa nn F-BBUOQUIMOME A. Borer, R. Klrchmavr, G.H. Rlst! Cibo-G«igy Ltd. A.a.lnumlar, A.ai.ahul'ga, O.F.GurinoTioh Institute of Phjaloe, Aceoaaj of Solaooaa at tha B33H, CU-4OO2 BaEBl, Switiarland. •ink, aaaa/naaa The nootoohealoaX nuclear polariaatioa (I) with natural Summary abundana* of Isotopsa haa baaa uaed aa * taohalq.ua for atu- The photochemistry of Bone v-substituted ocatophenone initiators ding a rarartibla redox prooaaa pnwaedlat »lth maalaation ia studied by 1H- 2O- and 13C-chamlcolly induced nuclear polarization of porphin eolutlons la tiia prsaenoe of n-bansoQulnaae. A / (CIDHP) experiments. The 1H-CIDNP spectra show polarization effects atroag auolaar polarisation of J'o o-benioqulnone haa bean from most of the important radical reaction products. The 2D-CIDNP obtained. As anhannad aigaal lntaaU.tr of oarbooyi groupa of experiments in favourable circumstances allow to follow the chemical qulaona under lUoBination amount* to 10* . A eonslAerably 13 aaallar intanaitT of the polarised aignal of I3ca quiaoae paths of selectively deuteratad groups. The C- CIDOT spectra carbons ladloataa that Ita radical fora exhibite dsmltr lo- characterize the main reaction paths and side reactions which are not calisatlon of an uaoaupiaa altotron on a oarboarl groups detected in the ^K-CIDNP spectra. In addition they allow for rough In depandenoa on tha atrootur* of porphina, tiia aoa* prc- estimates of relative C-hyperfine coupling constants. nooaead polarlaatlon offaota ara obaarrad althar an aacoaar- bona of a porpbln akalatoa or oa cUoarbona of n/rrola rtsgaw In some polymerization (scavenging) experiments, the monomer acrylic Iha ralatlTa aagaltudu and alana of auparflna intaraotLon acid methyl ester (SHE) la added at increasing amounts to the solution oonataata an indloatlTa.of tho altaa of pradomlnant localisa- of the initiator. The competition between photoreaetions of initiator tion of tha. uncoupled alaotron dtnaity at tha aoaanta of int«r- radicals with the JWE-monomer at small AME concentrations changes the aotion of lon-radlaal foraa of porphioa with qulaaaa radleala. CIDNP intenaltiea and givea inaight into the first Bteps of the It "naa baan fouad that tha Bain oontiibution to polariiatloa polymerization process. la that of radloal palra with non-oorralated apla* «lth thair raeoablnatioai

I, Bnfthf"llal>fcn AaX*« Chaaloal rolarlgation of Muolal and naotrooa, moaoo>, I9T4.

i ! A 3311 LUMINESCENCE QUENCHING AMD SPIN LATTICE RELAXATION IN ALKALI HALIDES AT VERY LOH TEMPERATURES G.LIIDJA and T.SOOVIK, Institute o£ Physics of the Estonian Academy of sciences, Tartu 202400, USSR

Hhan electrons recombine with holes trapped at 7. centres in alkali halidas, luminescence arises consisting of triplet (3t*»1I*) and singlet ('l**1!*) emission bands. At temperatures bilow 111 moderate magnetic field (below 20 kOe) quenches the cinglet. amiaBion, whereaa the intensity of the triplet band in- creaaea /I/. He found that the S-T conversion in n, Bbl and KBr could be explained satiafactorily with the statistical spin orientation in Vk aad F (or ?') centre pairs. In a magnetic field tha ground atataa of both centres split and at low temperaturea paira with parallel spins are populated giving af tar recombination the triplet excited atate of a salf-trapped exciton. Tha part of tha singlet emission intensity I,, which is quenched in some minutes after the magnetic flaid H haa Battled ia found to be "

with g - 2. Tha non-auanched part of singlet emission depends on the pair distance'. For clcaa tunnelling pairs I,(-1/1,(0) < 0,1. For the pairs recomblning after the optical relaaaa of electrons, this value lie. between 0.2 aad 0.6 at 0.4 K e=d increase, with aging. It i. not clear yet whether the "persistent* peire have vary long apin lattice relaxation tinea *SI or whether they lose thair apin memory during tha recombination. On the other hand, for the "soft* paira, aa determined in our luminescence experi- 2 ments TSI is of tha order of 10 sec at 0.4 K in fields of several kOa. That ia roughly consistent with the data of /]/ for F centra. In XI extrapolated to low temperatures.

1.* Liidja, G.6. and Sosvik, T.A. Izv. Akad. Sank SSSK, aer. fix., 41, 4B5 (1978). 2. Panepuccl, H. aid Mollanauer, L.F. Phys. lav. 178, 5S5 (1963). I 4 A 3101 • A 3402 ESR - SPSCTROSCOPIC STUDY OF STATICBAHY COOL ESR OF THE RADICALS SUMS OF DI3IHYL BTM3 T. Chen (Dschen) and Hs^. GUnthard, Physical Chemistry Labora- Z.A.MAH3PBOT. L.I.ZBUKO7A, O.I.KSA1IDOPULO, Kazakh Kirov tory, Swiss Federal Institute °£ Technology, Zurich, Switzerland State University, Alma-Ata 480012, D3SH ESR spectra of the radicals' CJFJ and CJHJ In liquid and solid Pre-olxed oool two-ataga flames of dlothyl athar and air eta- (natricas, generated by photolysis, will be reported. billted on tha flat flana burner have baan invaatigatad by tha The CeHc-radical formation from Hg is found to follow a scheme BSS mathod in conjunction with tba mioroprobe teohnique /!/. of the type Samples aalactad from tha flame by maana of quartz microprobe hv.U) hv,(2) were accumulated on tha fingar of tha Denwar vaaaal ooolad by — liquid nitrogan and analyaad by RE-13O1 radioapeotrometer. For Step (1) is efficiently produced by radiation of 254 nm and step tha first tin* radloala idantiflad aa peroxyl were detected in (2) already occurs at 334 nm (mercury lines). Tha yet unidenti- tha front of tha atationary oool flama of diathyl ether. It ia fied radical X reconverts thermally to C5H5* The liquid phase found that tha BSE aignal ahapa dapenda on tha distance between tha atabilized flaaa front and tha matrix burner. Thi'a, In aam- ESR spectra of both CJFJ and CjH5 are typical for systems with plea aalaetad from tha flame front, when it naa atabilzed eloaa S equivalent nuclei of spin i. For CJHJ the linewldth Is weakly to tha matrix, a splitting is obaervod in tha ESE spectra due dependent on temperature (0.13 Gauss at -100° C). In contrast to tha overlapping of two types of radicals. Profiles of tempe- CcFc exhibits a pronounced temperature dependence of the line- rature and of paroxyl radicals concentration were obtained along width which is also dependent of the total nuclear spin quantum 3 number m^. 1^ - -3/2, -3/2, -1/!, 1/Z, 3/2,5 5 tha atraam beginning Kith tha matrix. The peak of paroxyl radi- /2tAHpp - 0.45, cala concentrations ia in the region of tha firat cool flama 0.28, 0.13, 0.13, 0.32, 0.51 Gauss at -20° C). and la equal to 7.0 x 1012cm"3 with 12.5* content of athar. In rigid solution the C^F^-radlcal shows a more complex ESP sig- After tha first ataga the concentration of paroxyl radicala ap- nal (Fig. 1), indicating pronounced anisotropy of the couplings. preciably decraaaaa and in the blue flame region and over it *,t In contrast than the spectrum of the CjHj-radical (Fig. 2) which becomes insignificant, which ia rather surprising in oompariron remains unaltered even at low temperature. with tha profile of stable subatancaa atudiad by the ohromato- The following isotropic coupling constants were found: graphy technique/2/. She observed dacraaaa in the peroxyl radi- L3 12 C5H5 : ap J.5.99 G ; C C4H5 : a13 - 2.60 G cala concentration is probably caused by tha formation in the C C5F5 : a,, - 16.1 G region above the first flame cf radicala with small molecular weighta (CH^CHO^HO which do not fraasa at the temperature of liquid nitrogen. ^-

1. KssndopulD,' G.I., Koleanikov,B.¥., 0dnorogaD.S. Fiziks go- —Al raniya 1 vzryva, 10, 6, (1974).

2. VovellafC, Dellhourgo,R. Journ. Chamie FhyB., 6Bt No.9, r 1252, (1971). Fig. 1 Fig. 2

A34GJ A 3101 HBCXBOH SPHT-LATUCS BEIAXATIOS is. BADICAIS VIA ESE-SIUSX 07 qUANTUU PAHAUETSHE OF TIBRATIOHAL JfilXVKU BIASES A.I.lHKflAILOV, T.A.AHS0LSIK0 T.UBB0IB8ST, v-nrnxnT and K.HKH0V, larpov Institute of Physical Pepaxtanant of tha Chemical Kr/aiOB Institute, Chemistry. Moscow 107120, DBEE Academy of Sciences, Chamogolorka, Moscow, U.B.E.E,

Theoretical and expariMantal investigations of tha epin- An experimental pbyaicml modal haa bean developed for -lattice relaxation processes in a number of radicals with a m quantitative deaoriptlon of the electron tunnel transfer delocalissd unpaired electron have bean, carried out. process in chemical reactions fi,2] . The process is consi- It has been found that the temperature dependence 1^(1) is dered in terms of tba rat* constant of the thermal reactioni given by k,. aVaxn(-T/a)i whore V is a freqnaney factor, I ilu attenuation parajmeter of an underbarrlar/ electron vaTa^xttno- tlon! Z 111 barrier width. Rmdloal ions of dtffarant cha~ 35 •leal structure (TCBQ, tatraoymnatbylene, trlnltrobanzene • ' • »-# where A is equal to 10* and others) stabllliad In froien hydrocarbons (cumans, to- too 1 3 V 700 em" and -e~1O" » luene) at 77 E have been studied. The kinetics of radical so * 10"* aee. These procasaea ion amnlnUmtiem due to long-distance (30 • 60 1) tunnel 1 t ' axe interpreted as relaxati- transfer from anlons t'- cations la lndapendent of tempera- 10 on processes via exited Tib- ture In. tha ranga 4.2 - 110 I, this range being 4.2 to 350 K 5 rational states /1,2/. for the po3jiler matrix* Tha £S&-teohnlque was uaad for mea- Sea phenomenon of the surements. 1 * 10 15 . 20 thermobyatereais (curve 1,2) Tor most of the anions tha experimental Talnes of the is loyrj has bean observed and besi- wmve-funetion attenuation parameters are in a good agreement 10 2a 3D 40 50 0%T des tha extresal points on.' with those calculated from the rectangular barrier modslt the taMperature dependences' ft ••jj-fe «{«>*"/ where (.V - B) is an electron level depth of I1 (curve J) and of tha SHDQH intenaity have baan found. in an anion. Bu frequency factors wnich charaeteriza an lbs nature of these phanomma and their applications to extent of eleetron-Tibrational level coincidence In tha do- son physical chemistry problems are diacuaaed. nor and acceptop r vary with the typo of the acceptor within 33 151 1. Buroatsev, T.I. Puiyrer, V.V. fukhor, K.I. Oheredintoev.V.G. 10 to 1015sec~1. Different cations have bean found to causa Dokl. Akad. Bank 3B8H. 222, 155 (1975). changes in tha frequency factors, with tha wave-function pa- 2. VolkoT, T.I. Kuroatsev, T.I. Pukhor, I.I. eharadlntaav, T.G. rameters remaining unchanged. The values of a. paramatars Ils. Ivard. Tola, 15, 1230 (1977). and the number of tba anion conjugated bonds ham bean found to correlate. lbs obtained experimental results are dlsoussad. Ins KB-nethod allows the electron tunnel transfers through the barriers of sunersmell permeability (~ 1O"20) to the distances of several dozens of angstroms to be registered.

1. V.A.Anikolenko, A.I.Mikhailov, Dokl.A.H. ,23c, 102(1976). £. A.I.Mikhailov, V.A.Anikolenko, (In press). A3105 . A 3106 BUHSISR CV DHPAIHED 3PIS BKHSITT ?HDH AHIOH BADICAIS TO SOLTXRT E.3.E. STUDY 0? TBS imSHACTIOll OF HYDROGEN ATOliS WITH fOLT- DBHCJUEKD nt -SAOOAEIDES IH F8QZEH iqUHJDS S0LOTI0N3 OF SULPHURIC ACID. §& G.V.ABASgAH. Institute for iUjrsical Beseaxeb of the Armenian A.StUfco. A.TledC and Aoaasmy of Soiences, J78410 Ashtsxak-a, USSE Institute of Chemical FhTBiea. Slovak Technical University, The method Electron Spin Resonance (E3B) 1B applied, to the 880 37 Bratislava, Janslca 1, Czechoslovakia study and analysis transforming the free radicals resulting from the interaction of hydrogen ana deuterium atoms with inu- Recently /i/a nev posaibllltieB In the generation of anion radi- lin, dextran, celulloao and. carboxymethylcallulose in frozen cals toy means cf organometallle compounds were described. Inves- solutions of sulphuric acid (pH=1,5) at 110°K. At the same time tigatlng the Influence of various solvents on the process of the interactions of thoBe .compounoa laid on the surface of the sub- generation, it was found that the ESR spectra of anion radicals stance with great specific surface (200m /gr.), with hydrogen generated employing n-BnH in hexamethylphosphortriamide show an atoms generated in high-frequency discharge were carried out. extra splitting into doublet, not 'Sha SSB cpeetra of the products interaction of the hydrogen observed so far /2(3/. the glven^ atoms with polysaccarldes waa independent of the method of inte- Tlgure illustrates a part of PhOH" raction. Therefore the structure of polyeaccaridea in solutions spectrum at the lower field aide. ooea not changed, under the conditions of these experiments. It can be described by splitting Comparing the spectra of observed radicala in polysaccarides constants; SJJ-2,09 ml, 2xsg»3.44 with those of induced by interaction hydrogen atoms with their mT, 2xa^<0.2 mT, aJ-8.29 mT, which constituent elements^ mono and di saccorides! which, have been

are well established for PhCN" ra- studied previously /1(2/t an assumption has been made on the dical and taking into account all possible structure of observed radicals. In cellulose the se- the interacting nuclei. But, ad- condary free-radical reactions take place accompanied by ESB ditionally, the spectrum shows spectra transformation during the temperature increased up to a splitting into doublet with splitting constant 0.007 mT. From many possible explanations of this splitting, as Interaction with

counter-ion or formation of two isomera, the difference in their 1. Abaghian G.V. Apresslan A*Sa Dublnsfcaya A.M. Zh.FhyB. g-values being eoual'to 0.007 mt, the most relevant explanation. Ehim. 50, 38 (1976). according to our experience, appears to be the complex formation 2. Abaghian G.V. Apressian A.S. Studia Biophysica 64, 217(1977). between the anion radicals and solvent. The observed splitting is assigned to the phosphorus nucleus of hexamethylphosTihortri- amide', which was employed aa solvent.

1. A.StaBko, 1.faille, JUTkaC, T.AdamSik and M.Rronec Organic Magnetic Resonance, 9, 269 /1977/ 2. A.StaSko, A.TKaS and t.Kalik J.Magnetic Resonance /in press/ 3. A.StaSko. E.Halik, A.Krac and B.KaifaSova Zurnal fiziBeskoJ ehlmii /in press/

A 3407 A 3108 THE JBSS RADICAL TAtTTOlEBISli THE IBTERFREIATIOH OF THE E.5.R. SPECTRA OF s. p. soiOuovHiiroy, A. X. raoKOP' £/. H. H. BOBHOT • H. A. MAIICHEVA. HIIROnDB EIRADICAIS IS LIQUID AHB SOUS S0LUTI0S3

l.£.££U)ffl(KKATAtV.V.ERSEOtr,M.i.£A£ACHHaK.inBtitute of Orfia- A.IOIOHIH and T.flBKOB, Inatitnte of Chemical Physics of the no-Eiesen1; Compounds,Academy of Sciences,Moscow II73I2.USSR USSB Acsdexy of Sciences. Moscow 117977, USSR

The tautoneriBm of BOSS free radicals was investigated. It The eonsintettt theory of the BSR spectra of nitroxide bira- consists of the iotreaoleciUar migration of organic or elemento- dicals in both liquid and glassy solutions has been recently orgafitc trag»ente .between two oxT^en atoma in di-tret-butyi-?- pnblieheS hi. Using ita theoretical results, It is possible to -B~4X7phenoxj radicals inhere H is obtain extenelTB qoantitatiTw infoxnatlon about the dynamics of the intramolecular motion as well em the spatial structure of the molecules containing two paramagnetic centers. Studying the p thermal ebanges in tae 5SK spectra, one can define the type of The taJrtomeriam ravsolsd itself in toe specific widthneas in the spin exchange interaction (by both the rate and the strength), the lines at MSB byperfina structure.That allowed to calculate the number of the biredieal conformations differed by the Talue the kinetic parameters of tautomerisa.The other examples those, of the exchange Integral J in a solution and the character of the when the free valency migrated between six or four oxygen atoms eonformational transitions. in the free radicals,containing different elements,*ere studied. Xheznonynamle parameters of the conformations and* conxoxmati- enal transitions can be calculated: by use of rather simple pro- ~ o °C° cedures h! at the range of the 'effective conformations" concep- tion. It la the way to investigate the mechanism of the exchange E, interaction In the blradlcala as well as the influence of the solvent on it. Analysis of the blradleal ESB spectra in dilute It waa faun4 that the xregoency or flee valenc/ sieratioa l gleasy solutions allow,, to determine the distance R between un- waa Mora than Jf, Aa. Call anaatic protons Interact with an unpai- palrid electrons, the mutual orientation of the radical fragments, red electron equivalents) ana that cooroination nianer oftlie the magnitude and in aome cases the sign, of apin exchange inter- eleient in the UBS tiae-Ecale twcaae one unit asie conrared with action 3, even for nitroxide blradicals with B and/or |j|~ |A | the given valoncj at the hi h temporatui«.«t the lov tenpereSure 1I 8 fi,2f. If R5 13 I the whole Information on the spatial atractnre aa anpaiiea electron interacted with the protons at one ring of the stabilised conformation seems to be close to the X-rsy only.Tie values of tee intra- and j.nterH and exchange barriers 6 data, the problems how to analyse the experimental ESB spectra depend on the character of central atov and its Bubatitutes. and' how to determine the spatlsl structure and dynamic properties The reported exaaples illustrate the delocalization of a new of nitroxide blrsdicals, will be discussed. Icinav-the aelocalisation between bonded but not conjugated ^ft- T B7Steasl»ich is accoBpanied by thermally activated valency 1. Parson, .H.,Iokorln,A.I.and Znidomirov,e,M.Zh. Struct. Chem. migration with the roraation and breusse of the covalent bonde. 18, 152 (19TT). 2. Pamon.v.K. ,Iokortn,A.I.and BiidamlroT.O.H. J. Magn. Bes. 2S> J39 (1977). A 3409 A 31)10 A8UT5IS OF 5EB SER SPBCTHA OF FAIRS OF HADICAIS HTKRACTIOI is HE* PHOSPHOROUS DOBOIY. BADICAXS WHS iXUL 9THHBTRY A.T.ni'YA80V. A.SH.H0HTABOV, A.A.BAHLEV,- Institute of Organic S.N.JOHRTAXOV, G.G.LASARBV, M.V.BgUX)BOV. The Institute of and Physical Chemistry of the Kazan Branch Academy of Sciences Cbealeal Physics of tha leadtagr of Sciencaa of tie USSR, of the USSR, Kasan 420063, USSR Moscow, U S S S Bin structure and magnetic properties of a new type of Fairs of radical (PR) are tha important intermediates organlo stable radicals - phosphoroua ininoxyles, generated by in photo* and radlation-onenical reactions( but the interpre- chemical, electrochemical oxidation or photolysis of corres- tation of the ESS apectra Kith S=1 have not -been systematically pondins parent oxines, as well as with the help of the spin developed. trapping method, have been studied. Phosphorous tainoxylse are In this report we have analysed the spectra of pairs of shown to exist In two Btable uyn- and anti- isomsrs, their re- radicals with axis! symmetry and found new and more correct lative concentration and energy difference having been evalu- methods for determination the fine structure parameters and ated. the contribution of Loran* and Gauss »ith in the eeneral line The existence of apace isomers in f - mt oximes nave also form. Simple expressions for the absorption intensity was been determined by 1H and "p - BUR spectroacopy. This conclu- found, da expressions for calculation of the saturation curves sion 1B due to stereoapecif ic dependence of spin-spin interac- for the perpendicular and the parallel components in the aniso- tion constants. The possible reasonr nf the distinction in the tropio spectra were also obtained. Analysis of the ESR Bpectra geometry of oximes when pausing fro. tie diamagnetio to free with S s 1 allowed us to find the simple description of the radioal atate are considered. absorption signal* The spin density on phosphorous atom in fi - position is The method for -the calculation of the fine structure pa- shown to be transferred due to the overlapping of phosphorous rameters D and a by diagoaalinmg the dipole-dipole interaction a - orbital and that of the unpaired electron. The contribu- matrix la presented. The elements of abovementiohed matrix tion of the apln polarisation mechanism to U-, js- or f- were calculated by using spin density distribution. phosphorous atom has been evaluated, the spin polarisation of the phosphorous atom in eyn- and antl- iaomere being greatly different. The s- and p- orbital population of the unpaired electron on phosphorous is evaluated from isotropic and anisotropic SSR spectra, Borne qualitive relations for hyperfine structure eone- tants being found. The signs of phosphorous and nitrogen spin density are.de- teniined with the help of line width analysis, the peculiarities of intermoleculer motion modulating the isotropic hyperfine interation have been studied.

A 3111 A 3112

LUIS WIDTH ALTETCIATIIIO IS THE OHjCHjCOOH LSR SPECTRA En AND HEMOLUHIxEaCEIlCE INVESTIGATIONS OF LOCtGENINE I.Z.SIIULGX. V.A.0HISECI1UK, Institute of Nuclear Research of or CATHODIC MPOSITICK the Ukrainian Science Academy, 252650, Kiev, USSR D.BAJ.CEROWICZ, K.BALCEROKXCZ and J.lmalATA Among paramagnetic centers, which are formed in single crystals of fi -alanin after /-irradiation, a free radical CH^CH^COOK Institute of Physics, Technical University of Szcxecin, waa detected. The methylene group CH» which contains unpaired Al. Plestow 17, 70-310 Siciacin, Foland. electron is "rotating" with frequency )) > 108 sec"1 up to 4,2°K. When the sample temperature is above 20O°K the lino width alter- nation,ia obaerved which is inexplicable in the frame of ordina- tV% HUlimnti correlated-with tbenolumlneaccnce data ry kinetic-effecta. Authors sssume that low potential barrier of eeaeernini eleotrollals pnduets of lucizenlne in msthamllo

the Internal rotation of group GR2 already at temperaturea of solution fl,27 can be vary uaaful In the.determination of a 200°K provides the effective population of the upper torsion vi- schBM leeainc to the light emission. EPR data Indiaatad for brational levelJs. They correspond to states, close to a "free the exlatenee of three radicals, denoaiaated in the proposed rotation". Different valuesof the hyperfine splitting on protons acheaa bl'X, m^ and Ij. Kodlaal X la a short livln, one while by hyperconjugation will correspond to dif erent vibrational le- radicals 1^ and «j can b< detented iven after a few veaka. It vels, because of different space distribution of the unpaired was seen frost saturation curves that, elao apln«lBttlcc electron density. The resonance field value is determined by for- relaxatian tlaaa are shorter far X than far tj, Rj.

mula.' „ ?frHM- Tne preaence of KH*> dlMthylbUereaene (DBA) and HM'- "« ^. pi , where Jl - probabili- dlaethylUaondeapanalda (OUJ was confined by uv. ty of a free radical being found.on i-th torsion vibrations! le- Infrared and flno«eaesnee apectra. Theee products axpoaad t» vel and Hj^ - ita correaponding resonance field value for k-th the visible llsht and in the onaanea of 02 «lt during the combination of nuclear apina. Pi values depend on local tempera- aubeaqunt heatlni two different light quintal hi?1 and hi? 2, ture of the crystal region containing the considered paramagne- Cerralatlni the obtained EPS data with those from tbarmo- tic center. If the relaxation time of temperature fluctuation is luBlneaoanoe Huurmnti, the authors suggest the following longer or equal to the life time of the unpaired electron spin aohaae leading to tha light emission! Btate,generally will change from radical to radical. It 0M I 0, ^* moans that only such lines will he observed in ISR spectrum for DBAO >+M^-- -—DBAOi+X^Q which 'Ej^ (i . 1,2...) are equal. The width of the rest lines will be alternated owing to deep modulation of hyperfine interaction at frsa radical transition between torsion vibrational

levels. —IT, -* NMO <-Mt

wheret «J and aj arw (xoltad ateleeules srlglnsting frwai •1,

»2; ana MO la NHaatbylacrlaant.

1 K.laleera«lss sna J.SlawUakl, Asta rbys.Pal., A3). 237 /mi)

2 E.CJraien, J.B.Plck.tt. Js«.sap*, W.SaAngelu. J.Org. Chem. 35, 8S (1970) . B3li: . LEVEL NONCROSSING AND HMERFINE STRUCTURE OF ENDOR SPECTRA SFFBCTS OF A SSONG KKK0W4VE FIEU IN THE KNEOE A.BBIQg, S.ISHCHKSSO, I.KiTYASH, Institute of Geochemistry and A. Schveiger, M. Rudin and Hs.H. Gunthard, Physical Chemistry Labo- Mineral Physics of the Ukrainian Acadnny of Sciences, Kiev, ratory, Swiss Federal Institute of Technology, Zurich, Switzerland 252068, DS8R

ENDOR spectra of paramagentic centers with two or more equivalent The effects of a strong microwave field in SHDOE of solids magnetic nuclei show complicated hyperfine patterns for selected are reported for tha first tine. The experiaent is carried out orientations of the static magnetic field as demonstrated by the tor F -canters in. H.CI • Splitting of toe EBDOE linaa caused by a figure. For typical cases, e.g. porphyrin type metal complexes, strong microwave field in discovered* The figure shows this effect for Cl nuclei of a sphere n at T=300"K. The abscissas this additional complexity arises from repulsion of energy levels. represent the B?-fiel& frequence in MHz, the attenuation of a mi- This will be illustrated for two model systems crowave field power in dB is showed on the right part of the figure (zero dB point corresponds of the microwave field intensity 2v: ** evv • 2h! y*" *•- 0,14 oe). The dependence of splitting magnitude, the interaitieo and shape of the For arbitrary field orientation the ENDOR spectra may be approxi- splitted components for the nuclei from , mated with high precision by second order perturbation, techrlque. different spheres and isotopes versus the

: i If HQ lies on synmetry elements or in the direction of the magic microwave field power, orientation and tem- angle of tha electric quadrupole term, the second order approj.i- perature of a crystal and constant magne- or tic field mismatch have been studied. The matlon calculated in the direct product (C2v) the coupled lC2h) theoretical Interpretation is performed nuclear spin basis may fail owing to level repulsion. If, however, that allowed to explain the main experi- the nuclear spin.basis is symmetrized with respect to the symmetry mental results. The theory is similar to group of the spin hamiltonian, second order perturbation treatment the one described in /V for the Jntarauc- la still eccurate at the symmetry forbidden crossing points. This lear double resonans* At the same time is demonstrated for the C, system. Furthermore, the level non- in ENDOH case there are some qualitative crossing effects will be shown to depend on the degree of aniso- distinctions manifesting In a resonance tropy of the hyperfine coupling tensors. As an application of this lines number and intensity* The distinctions are connected with analysis the ENDOR hyperfine pattern in the figure is interpreted. the fact that in EHDOH only those signals could be registrated whose level populations are changed by microwave field transi- A similar discussion of a D4h system will be presented. tions /2/. The diatinctionB could be connected with a non-homogeneous character of an ESH-line broadening too. The SHBOE in a strong microwave field experiments give a new possibilities to receive an information about riectron-nuclear interactions, for Figuret instance about the mechanism u£ nuclear relaxation in the vici- type C2U copper complex, nitro- nity of a paramagnetic center. gen ENDOR, m •» -5, noncrossing; caused by vanishing quadrupole 1. Idppmaa S.T. Zh« Structurn. Him. t3, 717 C1967). term a. Brick A.B., Hatjrash I.T., Fedotov Tu.V. Fiz. Tverd. Tela, 13., 71 (1977).

B313 B3M

PULSED ENDOR IN DILUTED COFFER TUTTON SALTS KOLECULAR K0TIQ7IS AS STUDIED BY ELECTRON-ELECTRON DOUBLE RESONANCE (ELDOR)

V.A.BENDERSKII. S.T.KIRILLOV, N.P.PIVEN, Institute of Chemical Physics J. FOOE, W.Th. Wenckebach. H.J. Poulia (Branch), Acad. Sci. USSR, Chernogolovka 142432, USSR Eamerlingh Onnes Ubor*toriua, State University of Leiden

2300 SA Leiden, The Netherlands. ELDOR spectra [1] of nitroxide radicals (I) In plastic solids (cycio- hexane, d- and 1-carophor [2,3] and radicals with an anirotropic g-factor (II)

The paramagnetic single crystals (CU.ZQ) C»2 2 0 were in rigid glasses (ion-radical Sg in HzSz07, R02 in -y-irradiated polystyrene) studied. We describe these crystals theoretically with a thennodynsnic nod el were investigated 1n order to demonstrate the possibilities of ELDOR in the urosiating ol tevesal. •piniyitem*. Hcasuremat* were carried out in order to study of molecular motion. Upon saturation of a forbidden transition, con- gee info, mat ion about the thermal coatacta between various spinsy stems. These nected with the matrix protons, the ELDOR spectrum of I {ELDOR reduction exBcrimnts tnn performed in a 9 CHz. double renounce spectomerer at liquid factor as a function of the swept observing frequenoy) consisted of a narrow helitni teaperatures. asymmetrical line and a line with linewidth close to that of the ESR line. The changes o$ temperature of the various spiflsyitems are given by a This spectrum is attributed to saturation of discrete spin packets at the set of linear differencial equations. In order tt? solve these equations, pumping frequency (narrow line) and subsequent propagation of saturation aiaple boundary conditions are desired. These simple conditions are achieved throughout the whole envelope of the inhonugeneously broadened line (its by the application of r.f. pulses of very share duration (y sec) in an ENDOR hwnogenization}. The spin packet linewidth is related to modulation of the exparimt. This to-called pulsed ENDOR technique enables us also to measure anisotropic HFI of the electron and N nucleus by rapid (~10~** s) rotation very abate, contact-times between spinsyscems. of the radical in a plastic crystal. Relative random displacements of the -He inveatigatad the Chenal contact between t»e proton Zeenun system radical lead to variation of the magnetic field of proton environment and (ttS) and th* slietron dipote-dipole syeeem (EDDS) by pulsed ENDOR on the hence to homogenization of the line. The translational diffusion coefficients, protons. Becauit the energy at the PZS relaxes via the EDDS and cross-relaxa- c ••'•ulated from the relative Intensities of the narrow and broad ELDOR lines tion to the electron Zeeman systent (EZS), knowledge of the cross relaxation a.- Z to 3 orders of magnitude smaller than those for self-diffusion. This ci»e Tcr ia indispensable to determine the timeccustsut of the contact between decrease of molecular mobility in the vicinity of impurity correlates with the PIS and the EDDS fron these experiments. Pulsed ENDOR experiments on the the radical size. ELDORreduction factor of II is determined by radical rota- copper nuclei gi -e a characteristic t^« proportional to icr. So we are able tion frequency H(B) around the angle 6, given by the difference of the to determine x . ct pumping and observing frequencies. Comparison of the measured dependence of The crots relaxation tiae depends on the overlap of the far wings of the U(9) for the systems studied with those calculated in terms of models of ESR linea. So by changing Che distance between the ESR lines e.g. by rotating rotational diffusion and non-correlated jumps shows that the second model is the static field with regard to the crystalline axes, we can determine the in a better agreement with experiment. shape of the far wings of the line*.

1. Kevan, L. and Kispert, L.D. Electron Spin Double Resonance Spectroscopy. Hiley-Intersdence, N.Y. 1976. Ch.6.

2. Stunzas, P.A. et ai. JETP Letters, 17, 663 (1973). 3. Kirillov, S.T. et ai, Chem. Phys. •!>, 243 (1976). B321 B322 . ESR Of NEGATIVE ION'S IN LIQUID HELIUM-3 , SCHIBSS siBJurass c» EBB rat HIB pi SIJIEHCOHDDCIOBS J.F. BEICHERT. N. JAKOSIK, R. BSRRICX, Department Of B.I.IOCHBLUr, B.G.KOWSMVA and A.A.KOSOT, Kazan TJniTer- Physics, SONY at Buffalo, Buffalo, New York H260, VS\ slty. Is.ua 420008, TOSH.

He report the first observation of the magnetic resonance The paramagnetic resonance Una width In typa-II supercon- •pectra of the negative ion in liquid He. These experiments ductors with magnetic iapurltles is investigates. Helaxation are part of the continuing research program which had earlier processes Is a, spin system of looaUsed magnetic Boawnti and Pleasured and interpreted the ESR signals from the negative ion aondnotien jleotrons coupled by axohange Interaction are conni- in superfiuid He. The negative ions were created by field daxad lor umditiona of an "electron bottleneck-. 1+ is shown mission from a sharp tungsten tip mounted inside a sealed that tha dynaaio natnro of thla lntaraotios xasulta In a narrow- K -band~microwave~caVi£y.-VThe"ESR~spectra exhibits structure" _- ing of the S72 Una for paxamagoetio iapnrititts on troaaltion indicating either a hyperfine interaction of the electron in the from the normal to aupaxaonduoting state. According tothe cur- "bubble" with the nuclear moments on the surrounding helium atoms, rant theory, In »M.ch tha ijnamic nature of the exchange inter- .or the'existence of more than one species of-negative ions. He - action ia not taJcan Into account, there would be a broadening - have observed a pressure dependence of this structure -and will cf tha Una. The behavior of tha sm line broadaned bj the mag- report on the temperature and microwave power dependence of the natlD dlpol intaraotlonB on transition to tha laperoondnoting signal. The observed dependence of the initial polarization on atate ia inTeatigated. It 1B shown that the appearance of the 1 pressure for the ions in He is not seen for the ions'in . He. long isnga xonoaoi.Ufc.ting; contribution to the exchange coupling If A discussion of the magnitude of the initial polarization in of tha localised noawnta by ths oonduotlmi eltotrona In tha ao- both liquids will be presented. peroonducting state glres a oonclderabla narrowing of tha Bffl Una.. RM drr»lop«;', thrcrj la sosswred with •xparlmmtal ro- anlta. P.B. zimmermann, J.F. Reichert, A.J. Phys- Rev. 15, 2G3D (1977)

B323 ESR AHD SPIB-HSUIiTION FEOULIABITIES IN LAYER CEXSTALS S.S-IS , T.I.IOBOTALOT, S.U.OKDLOV and|ll.?.IgISmJ Institute of Semiconductors of tbe Ukrainian academy of Science, liar 252650, USSR Peculiarities in the Impurity K8B and spln-lattica relaxation temperature dependence are found for layer crystals. The experiments are carried out for tha layer semiconductors Bil3 and GaSe doped with different impurities. The phenomenon consists in prolongation of the linear temperature dependence of the spln-hsHltonian constants up to the temperatures such lower than Dsbye temperature and still sera gradual than usual the temperature .variation of the Bammn epin-lattlce relaxation ra- jtes In the above range. Tha theory la developed for describing the experimental re- T(K) sults. It explains tha sno*ali*s observed In tha temperature dependence by tha exlatenoe of low-frequency phonon modea in layer crystals connected with the weak interactions. Tb. low-frequency optical nodes typical of layer crystals are shown to bring tha essential contribution to tha apin- -phonon Interaction. The figure shows tha temperature dependence of the axial crystal field constant D aid spin-lattice relaxation rate T.,-1 for Bilj • an as an example. Tha points here represent the experimental data and tee aolid line reflects the .theory* Other possible explanations of anomalies observed are discussed. The methmd'HB ia shown to provide Information of the •tru/iwrj madificetion, pecullaritiaa Is layer crystal doping and xwatlaa; varies* tsrsurnetic ceatara. • B3301. B3302 m stretEos spnr scao unoia or na*Aiunous snofRU Dinusiai 1MB 3PKBIL vjMimvm n numn sra i.n.Haitalarlnn. K.M.Saliihov, Tu.D.Tavetlcov, Institute SCHO sncsA o» ucaceiDiciia of Cfcjaioal Kinetics and. Combustion, Siberian Branch D.O.OiljajltiJlnoT, and BJl.KUnahpant Academy of 3elenaea, SoToslbirsk, D8SB of Physical Chesistry, Moscow, DSSB Tha papar soon lias tha results on thaoratlaal and. experi- the phase relaxation of free radicals In polymers has bean Isvaatlgatad in electron apin-«oho (BO experiments of tha two- mental Investigations of tha contribution OS inatantaseoaa dif- -pulse type. It is found that tha evolution of a spin systea In fusion ta tha alaetron spin echo CM) signal decay of paremag- tha caae of Its partial excitation depends on th« correlation natle centers stabilises in solids. Ihia naelunlsm of phase rela- between ths BB line width (dU ) of tha radicals under investigation and tha magnitude of the exciting pulses (H,) as wall as xation results from tha dipolar interaction Between apis. A HHT on their position In tha Una 9 CW). If tha relaxation depends pule* realises " instant aneius" transfer of tha reaonant frequ- on the instantaneous spectral diffusion (JH^AU ), tha rala - ency of tha apine Inside tha dipolar Una contour In tha SB spe- xatlos rate distribution function dependant on the exciting pulse position is close to ths BB Una shape function. Ibis re- ctrum. Tne kinetics of ths two-polos BB signal decay to tha in- sults in broadening tha S3! Una (T(U,7 )) and its changing In stantaneous diffusion la described by tha relation ths ease of a single Una Into a doublet with tha intarpulaa time C increase, (tor axaapla for the phanoxy radicals! Tig.a). v(2O = T(0) exp {- 2 ot», t < 8^6/2 > /t g than tha relaxation whara 4«1/4 ia.th* dipolar lisa aldth, x is tha tlma Internal depends on the spec- between TJHP pulses, 6 la tha angla trough which tht apins turn due tral diffusion tXH. ^^AW )• tha to tha second BHT pulse ,<...>g ia the averaging over tha font of r= 2.0/

B3303 B33(W ELECTRON SPIN BESONBSCE BJf LONCITUDIilM, DETECTION: DEIWKEOH, LIT1DM MS StSBItJll HATBIX EitSOB SPXK-IATTXCE RELAXATION PROCESSES HEASUPSMENTS OP HUHCAI. IH FBCZEH SOLUTIOH M.GIORDANO, M.HARTIHELLI. L.PARDI and S.SRNTCCCI, Y.Y.TE01TBC. V.I.IffiBOICDSET, G.1.V1M0T1, D.N.SHXGORIS, Istltuto dl Fisica dell'Dniversit^ and Gruppo Hazionale Struttura della ntateria, Pisa, Italy Earpov Institute of Ehyaical ChemiBtxy. Uoacow 107120, UBSS

The recent development of a new technique of double trans- ENDOR studies of radical anion of enthraqulnone (/7fl~ ). ''versal resonant irradiation of a sample in paramagnetic resonance in frozen solutions were pertorned on Broker Physic SB 420 condition with longitudinal detection proved very useful for EKDQR spectrometer, modified on the basis of the patent /1/. spin-lattice relaxation studies. In fact, under not sringent EHDOH signals at deuteron, litiua and natrium larmor frequenci- approximations, the signal so obtained is shown to be.proportion- es as well as at proton frequency were detected. al to the spin-lattice relaxation tine. By this method It has - Results obtained show the existence'in a frozen solution been possible to perform measurements on samples endowed with so of i a} moleculaa containing deuterium atoas in tha nearest vi- I —16 cinity of ths radical; b) anion-cstion pairs consisting of a small TJ-TJ product values (about 10 sec) that other tech- radical anion and lillraHTie metal (lltlum or natrium) cation. niques, such as the saturation recovery, would Involve hard expe- Proton, deuteron, U?_ and Ha2' matrix: EHDOS spectrum at rimental difficulties. 100K of radical anion /JQ* in aetanoi (or deuterated aetanol) He h&7e studied the dependence of the spin-lattice relaxa- with 2-10"4 H/l alxallna (HaOH or IdOH) were found and studied. tion time on the angle between the crystalline axis and the Temperature dependences of matrix KfflXffi signala wars investiga- static magnetic f isld in a two-dimensional magnetic system (Hn2+ ted.

in a single crystal of (C2H5»B3)2MnCl4). The experimental results ENEOB advantages for studying the structure of radical fit very well the theoretical previsions obtained by the modified environment in frozen solution are discussed. Xubo-Tomita theory provided that one fakes into account as relaxation mechanism an lsotropic interaction besides the exchange 1. Muromtsev, V.I. et al. Art. avid. H 588491, Bui. OIPOTZ H2, moculated dipolar Interaction. 1978. The use of our r.ethod has allowed the study of the trend of the apia-lattice relaxation times at spin probe dissolved In a smectic mesophase. We have studied- the dependence of this trend either on the temperature or the angle between the magnetic Btatic field and the mesophase director. It is shown how the

~~simultaneous experimental determination of both I, and T2 relaxa-~~

~~tion times provides a direct Information on the trend of the P2~~

and P4 axd&r parameters as a function of the temperature without the use of best fit procedures. B33Q5 • B3306 DYNAMIC POLARIZATION: THE SOLE OF NUCLEI INSIDE THE DIFFUSION WEAK maatfjjg- vmairnvma IN VO2*-»ATER, HBTBAHOL BAKRIER COHFLKX5S STUDIED BI TBX KLBOTBOS SPTJT ECHO HBCBOS IH TROZBI GL1SSI SUUKIOU J.F. Jacquinot, o.v. Lounasmaa*, and C. Urbina S.A.Mianov, 7,7,101181107, Tu.P.TsvatkoT. Institute of Centre d'Etudes Nuelealres de Saclay, Dime ties Merisiers, Boite Chemical Kinetics and Combustion, the Soviet Academy of Postale N° 2, Gif-sur-Yvette, 91190, France Sciences! Siberian Branch, Novosibirsk 630090, USSH He show that at certain levels of irradiating power the A novel ijproach to investigation of .weak hyperfine Inter- speed or dynamic polarization in a single crystal can bo increas- actions (hfi) between unpaired electrons of paramagnetic comp- ed. This happens when the specimen is oriented in such a way that the NHR frequency of a nucleus, which is a nearest neigh- lexes and magnetic nuclei of Uganda as veil as obtaining infor- bour of an electronic impurity acting as the center of polariza- mation on the structure of complexes In solid disordered mat- tion, coincides with the NHR frequency of distant nuclei. The rices are associated with, the analysis of modulation effects nucleus in question will then be in "speaking terms" with nuclei outside the so-called diffusion barrier and dynamic polarizaticn in the electron spin echo (BSB). can proceed through it by spin diffusion. He have studied ex- 2 ;. In TO * complexes with Da0, CHjOD, CDjCR the unpaired perimentally this effect in CaF2 doped with Tm and we could electron has an axially symmetric J -factor. The modulation of observe an enhancement of the Bpeed of dynamic polarization by a factor of five. This increase is larger ac low values of irra- the primary echo signal decay of these complexes depends es- diating power and one may thus use this effect in an apparatus sentially on the value of the internal magnetic field and the where the amount of hyperfrequency p*:wer that can be dissipated

nature ( 4nor Jji) of the BBR spectrum line excited by micro- is limited. wave) pulses. %e modulation of the primary echo was calculated taking into account the axial anisotropy of VO2* complexes and * Present address: Low Temperature Laboratory, Helsinki Univer- the structure of the first coordination sphere. The comparison sity of Technology, SF-02150 Espoo 15, of exparijnent and calculations givas the hfi parameters charac- Finland

terising the complexes structure. For example, for VD(D2O)|* complexes tie distances to equatorial, 2.1 A, and axial, 2.9 A, deutens were found. The constant of the isotropic hfi for equatorial deutons, e^= (1.0+0.1)cos2p+(0.4+0.1) KHz .was also obtained as a function of the rotation angle f of a water molecule with respect to the equatorial plane round the ion- ligand bond. This angle varies within 50-60° as it follows froa our results.

B3307 B3308 TEST OF IMPROVED MATRIX EHOOR LIUE5HAPE HODEL BASED OH IIPOI SPECTRA CAICTIATIOH SINGLE CRYSTAL DATA L.ASTSIPEROVA. A.TOBOVA, T.KUIAOIHA and H.PIVBH LAR»T KEVAM. and P. A. HARAVAHA, Department of Chenlstry. Wayne State University. Institute of Chemical Fhysios (Branch) of the USSR Acade- Detroit, Michigan 43202 USA and my of Sciences* Che^^A'tolovka 142 432, Moscow Region.USSR K. TORirAKA AHD H. :«K5AM. Covernaeftt Industrial Research Institute. Hacoya, Hirate-macht. Hta-ku. Hagoya. Japan Electron-electron double resonance in dilute solutions of slowly tumbling paramagnets, when molecular reorientatlon is An Improved Hneshape model for the matrix £NDOR response near the free nucleus precession frequency In disordered systems has been developed and the dominant spectral diffusion neonazism, can provide direct appUed to a S-l/2 1-1/2 spin system using a density matrix formulism. The information on much Blower rotational rats as compared to KiR model Includes the radlofrequency and mlcroHave field intensity as v-ll as experiments /1.2/. We present here the calculations of ELDOR different spin relaxation paths explicitly. This- Improved model has Been response carried out employing the stochastic Liouvilla method tested with single crystal data on methyl radicals in gamaa-Irradtated lithium 151, And the interaction of spin system with both the applied acetate dlhydrate. Comparison of the angular dependence of the ENOOR Intensity radiation and pumpine; fislds oX frequencies lO a lOp i res- of matrix protons from the single crystal data with the llneshipe model pectively, was 'taken into explicit account. The adjnpleat oass allows us to assess the Important nuclear relaxation mechanisms that contri- of a single line broadened by an sxial-eyisnetric q.--tensor bute to the ENDOR response. In this particular case we suggest that the is considered* The jump model of molecular reorientation has angular dependene of the ENDOR Intensity Is weak because of a relatively been usedB An iteration procedure to take into account the fast nuclear spin lattice relaxation rate for the protons In lithium acetate contribution of higher hamonica of iVp — u) which became dihydrate. essential when «)p —«?—0 has been developed for numerical calculations. The parameters employed wars obtained from ESR and ELTJOR experiments with lon-radioal $£ in eondentra- ted oleum. Calculated data are in agreement with experimental, Ths eoaparlson with spectra calculated on the basis of diffusion model /2/ shows that ELDOR technique is 'sensitive' to the character of molecular motion in slow-tumbling region.

1. Smigol.M.D., Dalton.L.E., Hyde.J.3., Dalton.L.A., froc. Bat. Aoad. Sci. USA. 71, 1925 (1974). 2. Bruno,G.V., Freed,J.H., Ohm. Phys. Lett. 25, 328 (1974). 3. (a) Korst.H.H., Lasarav,A.V., Kol. Fhys. 17, 481 (1969)1 (b) ?reed,J.H*t Bruno,C.T., Polnassek,C.F., J. Phys. Chem. 75, 3358 (1971). V

B33Q9 B3310 2+ ELECTRIC FIELD GRADIENT AT THE l576d NUCLEUS IH CaFj : Gd3*. M*. STHUGTURS DKTKHHIJUTIOII 0? TWO Un PABAHAGIIBTIC 0BOTBR3 IN oC-LUOj M THE RTOS ADD EBDOE METHODS D. VAH ORHOimT. J. AHOR1ESSEN and 0. DAM, Technlsche Hogeschool. n-M.inBj3RT.Tt A.BRXUEa*and R.BOTTCHBR**, Tbilisi State P.O. Box 5046. 2600 G». Delft, The Netherlands - University, Tbilisi 380028, USSR H.H. JEN h7WTO6 and E.J. 3IJVAHX, Solid State Physics Laboratory, 1 Helkveg., Groningen, The Netherlands. In the prsaant work ualag radlofrequency diaorete saturation (WDS) and EBDOH methode we have investigated the hyper- 2 The ground-state splitting of Go3* 1n a crystal, represented by the fine Interactions of two different types (k and B) of Hn * pa- tern ^ (3sf " 52) • 4 (5x " ^'' u *" a1Micu1(; t0 «Pl»*n quantitative- ramagnetic oentsrs in m-liJOj singls orystala IM and deter- ly IV. Bijvank et al have shorn IV that if Gd3* is substituted at a diva- mined the substltutional modsls of magnetic lona. Angular depen- 7 2 lent site of i cubic lattice (CaF2. BaF2, SrCl2) the values of B§ and s|, ob- dencies of Li spectre were Investigated at 2 K; «n * concentra- 3 served »hen the necessary charge compensation Is nearby, art such easier to tion waa about 3-1O' mole St. explain. The reason for this Is. that in this case the values of Bj and B| are It is shown that Un^substitutes Li* ion in the lattice, due only to the charge ccopeflsation and possible local distortion, the con- compensation at the excess charge being performed by the vacan- tribution of the rest of the lattice being zero because of the cubic symetry. cy of one of the neareat Id iona along the hexagonal crystal As charge compensation they have used a sonovalent ion H* (n* > L1*,....Cs*) axea. The formation of two types of the centers (with different substituted at one of the taelve nearest cation sties. parameters B°,) is related to the two possible positions of li- In the present mrk the ground-state splitting of the ' Gd nucleus in thium vacanoy along the axee to both directions from magnetic 3 2 CaFz ; Gd *. H*. represented by the tern r\ (3l| - I ) + P^ (ij; - I*), 1s ion, because of the lack of inversion symmetry at the lithium studied by aeans of EKTJOR. H* being LI* or K*. The measured values are (in sitss* This la the reaaon of different diaplaeementa of sur- Mte) P§ " '3.40. p| . -18.79 for H* - Li*, and P§ . 0.261. f| - -17.320 for rounding lithium ions from equilibrium positions lor two cen- H* - K*. Comparison with the corresponding values of B§ and s| 111 reveals ters. The values of theae diaplaaementa, aB well as correspond- 2 that there is no simple relation betveen the electronic and nuclear ing quadrupole splittings hsva been determined, an * wss found splittings. As a result the sign of the local distortion in the z-direction to displace In the vacancy direction at 0,19 * 0,05 A for A-cen- calculated from the electronic data III Is opposite to that calculated In the ter and at 0,3 ±0,05 I for B-center, while in the caee of present study. It tend out that the Steraheiaer antishielding factor for LlJO.i 7a'* there Is no displacement of fe becsuse of relati- the nucleus is almost isatropic and cannot be held responsible for this fact. vely symmetrical poaitions of two compensating vacancies 121. Details of the theoretical calculation of P° 1-J >*|. including overlap The comparieon of an with Fe** end Cr^* in o< -LU0., b.aa been effects, trill be presented. carried out. 1. BrSuer, A. and Karthe, jf. Phya.St.Sol.(h) JJ. K131 (1973) 1. Neman, D.J. and Urban, II. - Advances in Phys^s 24. 793 (1975) 2. Brauer, A. and Darasalia, E.I!. Piz.tverd.Iula V£, 1250(1977! 2. Bijvank. E.J., Den Hartog. H.H.. Andriessen, - J. Phys. Rev. B 16. 1008 (1977) + Department of Physics, Priedrich-Shiller-Uaiversity, Jena, CD8 ++ Department of Fhysies, Karl-Harx-Univeraity, Leipzig, GDR

B3311 B3312 i INVESTIGATION 0? THE ROLE 0? THE Cooling of the nuclear dipole-diDale resei^cir due SIK>LE-DImS RESERVOIR IH THE DISTANT Hi DOR S zicrovave and ODtical pumping of the paramagnetic cenrera RUB! in solids. I.H.ZABITSKII, A.A.KCSCB1TC. B.D.SHAlEI/l, Insti- T.V.Poirortsev,Institute of Chei3i.cal Phyalcs of the Ac&detny tute of Semiconductors of the Ukranian Academy of of Sciences at the USSB.Kosccw 11733'(,rjSSH. Sciences, Kiev 232650, USSH At I - 4,2 K the dependence of the amplitude of tin. distant A xechanism is proposed for the electron-nucleor EBDOH (SESDOR) signal on toe field deviation from the ESR line spin-3pin relaxation ca'iset1. by nuclear spin flip-flop center and on tba microwave and radlofreouency (Prf) powers hSB 1n?ansitlan& /i/.Bauntion-t connecting the polarisations been Investigated for different orlentationtof the external mag- of the spin packets in an inhomogeneously broadened GSR netic field Bo In Al2o,:&^*(o,o2atf). DEUDOK danamlca of speci- line with the inverse teaparature of the riucle&r dinole- fic character have been found that can not be deacribed by eiia- dipole reservoir /HTJDR/are derived. A consequence of tlng theories Included the one taking Into account the dipole - equations ia the possibility of cooling the NDDB under dlpols reaervolr (DDR) of paramagnetic centers , though tbsre is the influence of & microvave field of frequency^}. The qualitative agreement with the latter. This may bs connected to inverse temperature of the NDDH in the stationary at^te the unustal aaturatlon behaviour of the SSR line retaining ita is given by: « original Oauaslan ahape tut broadening In agraeaent with Ixovo- torov'a theory for Lorentiian llneshspe. lor orientations of H,, A* corresponding to crosa-relazatlonaa angles la ruby (••2cT9ani

~~54,7°) an anomalous dependency of the SENSOR intensity on Srf~~

~~was detected) the algnal dleappeared .on increasing prf. Apply- Hare/J la the ehift relative to the BSR line center^ I a~~

ing an additional radlofrequeney Irradiation tola affect waa itwersa temperature of the latticefy^« is the NDDR spin lattice found to be of nonrasonant character. An explanation is offered tinte,^/^iB the sacood ooment of the SSR line shape, X) is by aastadng heating of the SDH by P_. l account of tbs oross - the ••an tncfpAj of the nuclear flip-flop transitiona. '{• ralaxatlonal suaesptlblUty inoreaeed due to saturation of the In the case of optical pumping of the paramagnetic 'I:. BSR 11ns wing. In sgreaaent with direct experlaanta of smtui'a • center pairs the effect of the optical cycle is to populate '§.; tion of the ma by alternating field /I/. It should be pointed preferentially the singlet ground states of the pairs /2/. ~> - ' out that a radlofraauanoy field perpendicular to Hg haa a auch On the other band.according to our model, the populations 'f stronger effect than a parallel one. This la due to tbo strong of the electronic levels of the pairs depend on the temperature magnetic salsotropy of the object Investigated. Sines for low of the TODR.The theoretical treatment esteaatefl the relation

values of Prf DESDOR dlpaalcs is Identical for all orientations between these nnantites. of H^ (included also 0 -Z8°sn4 54,7°) one can deduce, that BEH- DOH la ruby la connected to the dspolaMsatlon of nuclei dwna - laPcmnrtsev W.V- Sov.Phys.Solid State 17,1146 /1975/i •leally cooled by the direct thermal contact with the DDK of Fomortsev 7.7. Zh.Bxsp.Theor.Fis.72,1SO/1970/. v paramagnetic centers. S.Taccard C.SnenE P.A.,Aecerter V'.,I^s.stat.s .: • 1. Atsarkln T.A., Byabuahkln O.A., Skidanov V.A., ZBETIB, li. lil8, (1977) V

B33I3. B33W DYNAMIC SUCLEAR POLARIZATION OF 7LI HESONANCB SPXITTIKG OF EFH L2HB BY INTENSIVE RADIOFEEQUEHCX IN SOLUTIONS OF FREE RADICALS FIELD AIID HIS DISPIAT IN ENDOR Karin MEISE and W. MULLER-HAHHUTH, Institut fur Physikollsche V.G.GRACirev, Institute of Semiconductors• Academy of Chemie der UniveraitSt HUnater. V. Germany Science of Ukreinisn S£R, Kiev, 252650, USSR.

Interroolecular dynamic nuclear polarization {DNP) was so far The wellknown aethods of description of the one sort nuc- preferentially applied to 1R, 13C, 19F, and31 P nuclei o£ nou- lear line splitting by intensive rf fi«ld on the Larmor frequen- tral molecules in colution. In extension of recent studies of cy of another sort of nuclei /1/ wer& used for electron-nuclear POTENZA et al.1'2* 'ld.-DNP has now been used to study transient system. It was shoved, by transition into rotated frame that the complexation and collisions of lithium ions with both free radi- resonance SPK line splitting is equal to (e/2iyn)H2/Hi where a - cal ions and free rtdical molecules in the liquid phase. DNP is the constant of hyperfine interaction, vQ - is the nuclear data was obtained for several LiVradleal pairs at various tem- Larnar freriencj- in the static magnetic field H» Hg - is the peratures in a weak magnetic field of 17*6 mT (NMR frequency: amplitude of rf field. This kind of splitting could be registra- 292 kHz. ESR frequency: 494 MHz). For some cases relaxation ted with EKEOa for the sharp homogeneous lines. The strong de- times or contact shifts have also been measured in order to sepa- creasing of BPB signals in the center of line should be obser- rate dipolar and scalar contributions. Particular emphasis has ved, when rf field is applied, whereas the insignificant in- been laid on Ion pair systems in concentrated solutions of creasing on the Bin^s • The inhomogeneoua broadening leads to lithium ions and aromatic radical anions. For ion pairs with (b/c)^ reducing of the effects, where h - is the width of homo- naphthalene, blphenyl, and anthracene anions positive Li geneous spin packet, c - the width of the packet distribution enhancements are observed which depend in detail upon the function. The simultaneous splitting of several components of ethereal solvent and which become negative as the temperature the SFH line hyperfine structure aa well as the saturation decreases. The data has been analyzed using the concept of an BNDOR signal with H2 increasing and the nossibility of the equilibrium transition ?icm solvent separated to.contact ion BNDOR registration in the snail microwave field are the typical pair? 3J. With biphenyl a detailed evaluation of t*ie scalar and features of the considered mechanism. The comparison between \ dipolar contributions and their relation to the ion pair struc- the developed theory and tho negative EHDOR experiments /2/ w8s ture was possible. Different enhancemencs apd structures have carried out. been found for ion pairs with chelating radical anions and TCNQ • In solutions containing various nitroxide radical molecules 1. Lippmaa E.T-, Journal of Structural Chemistry, 8, 717. 1967. enhancement factors and contact shifts of Li appear to be 2. Uiyagawa I.f Davidson R.B., Helms H.A-, Jr., Wilkinson B.A-, sensitive upon the electronic structure of the radical, rm the Jr., J.Magn. Res., 10, 156, 1ST3. polarity of the solvent, and on temperature. Scalar contributions are estimated and discussed in terns of the formation of weak solvation complexes and their lifetimes.

~~1) J.A. Potenza et al., Kol. Phys. 29, 1597 (1975) 2) B.E. Wagner et al., J. Am. Chen. Soc- 98, 4405 (1976) 3) G.w. Canters and E. de Boer, Mai. Phys. 26, 1185 (1973)~~

B3315 B3316 DIHAMIC HUCL24H POIAHIZAIICH IH LIQUID SGLUTIOKS 2HD0H OP Yb3* IH PEHOVEKITB TIPS CRYSTALS OP Tim AHD Fe1 COUPOUHBS M.L.PALIH. V. P.MEIKLYjm and B.S.KUUU, Fhysico-Technicsl T.K.?ED0T07 and B.II.0DIHTSC7,Kazan Physical-Technical Institute of Kazsn Branch of Academy of Sciences of the Institute of the Academy of Sciences, Kazan 420029, OSSH USSR, Kazan 420029, USSR In spite of the first investigation of dynamic nuclear po- 3 larization (ISP) In liquid solutions of paramagnetic Ku11 ions The transferred hjrperflne interection (TIIPI) of Yb * with 19 carried oat 07 Bloembergen fit as tar Dock as in 1958, up to the F nuclei of the 1-4 coordination spheres in perovakite type present tins only four transition element compounds have Seen crystals (KMg?3,KZnPj) was investigated by seans of electron- stiided. Ihey ar«: mp, VCT /2/, CrT, koV /3A A few natter of nuclear double resonance (KH703). Tiie -parameters of the ieotro- works accounted first of all for relatively short electron pa- pic and snisotropic THFI were obtained. The determination of the roaagnetle relaxation times of these system in solutions. sign of thsBe parameters wss carried out basing on the fact tost the effective spin projection in the field direction, , This report deals with the results of IDF investigation of differs sppreciably from + J when E1DOE on odd "J Yb'1" isotopes two new complex ions: II111 and I.1. In order to get necessary wss detected. The vsZue of this reduced spin < S > was calcu- pumping radiation in the sample volume, the aierowave delay line lated from the eigenfunctions for each hytierfinn state, obtained (helix} was used. Haussar /4/ was the first to apply helix to by diagonalitation of the hsmiltonian. A "frequency shift" for IMF. We've investigated DSP of protons la solutions of some nit- f9P nuclei of the second coordination sphere due to the change rosyl coapaxes of ooaralent irons la nagaetio fields 30, 200 and. < Sg* enabled to determine the signs- of the parameter of the 3300 G sal aads the conclusion that dipolar latemlecular nypsr- hyperfine interaction '"A. the estimate of the local distortion flne interaationa jreTail. Tie small value and temperature depsn- of the crystalline lattice in the vicinity of a parsmagnstic danoe of nuclear-electron eoupling. paraa«tar In Tl compounds centre dus to the difference of the ionic radii of the cation and indicate that besides basic dipolar in relaxation of solvent no- the dopant was carried out. The position and intensity of a spec- leeulee there exists scalar contribution. In solution of inves- trum of the transferred hyperfine structure of the Xb3* BIB line tigated compounds to* molecular motion, electron relaxation times in X- and Q-bands for different orientations of magnetic field and some kinetic parameters have bean studied. The conclusion wms were calculated using 'forbidden traditions" formalism end HTOOB Da.de about structure and transmission of uncoupling* alsctron dsn-- data. The dependence of the orbital reduction factor k on the sit? to the solvent for one of Tl111 complex. It should be noted diatance tb-ligand for different crystalline lsttices with octa- that the Ugh polarlsatien degree 75/ in did complex of CrT,»e'd hedral symmetry taking into account local distortion was consi- investigated fif, mads it passible to use it as an effeotivs pro- dered. ten polariBatl»n target /6/ Instead of classical UtT-targst.

1. Codrington.B.S. and Bloenbergen^T. J.Chem.Jhja. 29.6OO.CI958). 2. mcCaln,Ii.C. and myars.R.J. J.Chm.Fhjs. 71, 192 (1967). 3. Jedotov.V.S. JUP, UBBH, $3, 1982, (1967).- 4. Hausser.I.H. and Helnbold.F, ZJIaturforsch. 116,1114 (1961). 5. Borghini.ll. st.al. Buel.Instr.llethoas 10$, 21$ (1972). e. OUttli.H., Odehnal^l. at si. Phya.tet. 291, 250 (1969)- liV'i"' B3317 or THB DIBTAITOI DKTRIBOTIOH or ion HLXHS at no mnn 3FIW ECHO IBCHHWS S.A.Ctut*. l.II.Baitalwring, Tu.D.favetkev, Institute of Chemical Klnatioa and Coabustion, Siberian. Brush Icadeay of Sciences, Novoaiblrek, DBBB Photochemical transformation of iona wit* tranaiant valency la solid aatrices oftan reanlta In foxaatioa of atabla radleal- -paruuignetic ion pain. H»gn«tle iipolar intaractlons la ntft pairs allow one to in.-nstlga.ta tha law or tha Olctane* Us trlou- tion of tlitsa paira using tha slastzon spin eeho ttehnlgu [1]. Tho primary •coo signal dsoay of radical rwultiag from tha Intara- cticm vita tha ion is dataninad froa tha axpraaalon [1]

*C?i) * =p {- T>tfBW..* 1> W,(1 - } ooa«e)«}, (1) wnara x is tha tiaa interval between proDing polsea, ^ is tha spin-lattice relaxation tint of tha Ion, 6 la tha angle ostnaa tha vector r connecting both particles aad tha direction of tha. external magnetic field. It follows from the asm formula that la a United region round the ion where tha signal is close to sen. The aize of the region varies with T and-T • Tariatian of the signal intensity is associated with the spatial radical distribution with respect to the ions. .ft This aethod is used to Investigate the distribution of tha radicals resulting fron ?e'+ ion photoljaie in alcohol glasses. The tlae T^ varies by several orders with teaperature changing.The photolysis mechanism suggested in photoehealstr; bas been verifald. [1]. Salikhov K.«. • Senyonov A.fi., Isvetkav lu.D. Electron spin echo and its applications, "Wonka.", Boroeibirflfc, 1976.

~~i V~~

C311- C312 B1DI03IKIH03C0PI0 ISTBSflOUIOH « ACOUSTIC HUCLKAR SHH ECHO IH ASTIPSBBtaCAGHBTS • E1ECTRCUCOUSMC EOHOgS KRaG.B0QSAI0TA,7#A,GOimSBCHR7-KtnUZ0T, S.A.ZBIDOVICH. G.A.SUQlEBSia, B. i.TiBurwng- H.N.KRAIBIK, S.H.POPOY, A.R.KESSEL.A.A.MOHiXHOT. .Ihyaieo-Technical Institute of the Academy of Sciences of Xaian Physical-Technical Institute, Kazan, USSR the USSR, Leningrad 194021. USSR The theoretical and experimental results of the investigation of acoustic spin echo phenomenon excited by two KLectroaeouatic echo was initially observed in ferroelec- acoustio pulseB on the nuolear spin systems qf the antifer- tric single crystals and pieso- and ferroelectric powders. roaagneta are reported* Calculating the coupled Bystern of The annaroonic-oaoillator mecoanlan la consisteot with the ex- the equations for the nuclear magnetiiation and elastie perimental resultB. She electroacouatlc-eoho phenomenon has proved to become a new branch of radiospectroscopy and a new theory we obtain the following expression for the rcoustic tool for aolid state investigations. A practical use also be- eoho-respance _ ih--Jtc~ % comes evident. A new push to the echo investigations has been made by the discovery that the time relaxation constant, T.., where U)% iB *&B nuclear frequency. £J"io tha sound velocity, can under certain conditions exceed any dynamic relaxation time J5 XB ttw density, ^ is the angular turn of the nuclear mag-

in any material. In this report some results of the radioBpec- netisation for the 6-pulse. Ma and M0are the equilibrium troicopic investigations of the echo phenomenon in pieeo- and values of the nuclear and electron magnetisations, Gj is ferroelectric crystals and powders are presented. The physical the magnetostriction coefficient, H_ and H tha exchange and

~~meaning of the echo parameters - time relegation constants, hyperfine fields, tfXxis the element of the acoustic strain~~

T1 and T^anfl extrapolated amplitude - is discussed. Tha echo tensor, 6 is the angle between HQ and kT, Q is the Bessel relaxation measurements in bismuth gezmanate are compared function* with the results of other methods. The anomalous behaviour of the acoustic spin echo signal was observed on the nuclear the echo parameters in the region of ferroelectric phase tran- 55 spin system Un in a Klt^ single crystal at 4,2°K. the ul- sition in ferroelectrica of different types haa been investi- trasonic pulses.were generated by a LLHbO* transducer bon- gated. The dependence of the echo parameters on linear and ded to one face of the crystal- Tnr echo signal was*detected non-linear elastic and electromechanical properties of cryst- by a transducer bonded to the opposite end facs of the crystals ia discussed. The necessity is shown ^o tafce into conside- tal- The pulse of the longitudinal acoustic nave was propa- ration the nonlinearitie8 of higher order than it has been gated along tha cristal oiia Jiooj and excited the nuclear done before. The possible mechaniwn of the long-time storage spin ayst*m at the resonance condition. After the propagati- effect is discussed. on of tha second acoustic pulse with the time separation 4*3 Zbe possibility of using the electroaconstic echo for mea- jHsec from the first exciting pulse the acouBtic echo signal eurements of the nonlinear electroacoustic interactions, sound was observed. From our experimental resalts it follows that attenuation, sound velocity temperature dependences, the pro- moment of the echo formation, its intensity and angular de- perties of the phase transitions, and aconatic waves interactions pendence are in agreement with theory (equation X )- with exyatal imperfections is discussed.

C313 C3W REORIESTATIONAL HOTIONS IN FERROEtASTIC AND FERROELECTRIC CRYSTALS" nuciDiiiois n DAVID C. Atlim and HAROLD T. STOKES, Departmat of Physics, University iv siHoas jusiraic HELD of Utah, Salt Ufce City, Utah 84112 USA

Alkali cyanides (e.g., NaCN and KCN) typically -ihibit bath ferro- M.A.SiVCHBKO. A..V.3IBPHl»0tICH. M.A.KBAB1XBFASBIV, Ioatltute of eluticity and fernwlectricity and exist in three phases in different Redieengineering, Faectronlea and »utoa»tlc», Hoecew 105275 USSR temperature ranges. Vie low temperature phase is aneiferroeleciric anil the CH~ ions are aligned antiparallel. At inteimwdiate teftperatures (i.e., Bx nethod of renermallutlen greep In dlaanaion d"A-E It between 172*K and Z88*K far KaCN and between 83"K and 16S"t for KCN). the la ahown that the phaee tranaltlen in rerr»«leetreentlT«rroMg- phase is ferroelastic but paraelectric in which the CH~'s are aligned along neta In etrang ugnetlo field at "collepeing" et the aagnetie the II10I directions but without preference to polarity. At high tempera- momenta of aublattiee. it preoved to te the first arder phaae tures the CN~ ions reorient rapidly and the crystal is paraelastic. Me traneition near to tb« seeead order at Uenaero eonatant of the report the results of Tj and T, neasureaents of the I3C in 90\ enriched nagnetoeleetrie intaraetien and anjr valuee of dlelaetrie permea- UMCH over the teoperature range room temperature to liquid nitrogen as well bility. The relativlatio Hagnetoeleetrie eorrelatian ia ahewn to as possible interpretations in terns of reorientational notions of the CN . "diirupt* the tranaltlon an effectively than tha volume exchange etrlctiea. The value of the diaeontinuance of the order "This research has been supported by the U.S. "Jational Science Foundation perumeter (tbe aadul of tha autifer> under Grant MR 76-18966. remagnetic vector) and the value of U the critical field ahlft due to the fluetuatioaa are calculated. The eoft ferroelectric aede frequency U> and

!i\w i | , the elastic aodul are ahewn to have the anomaly In the phaae tranaitlon point at "eollapaing". The dependence a>(H) la brought on the figure. Tnen eoci the value af the order parameter diacantlnaance ia exponentially email. The heat capacity and the mag- H netic aueeeptlbility are then the following:

~~where~~

~~A 1B the order parameter dimcnelen. V~~

p C321 CJB COHDUOHOH KLBCTROI sna SCATTBHIKJ oi no HOUHUBY ntH 0B tBi IHWBT Of ID MB 1IBBHKTH IB URIIS B.P.3BJOI1, Institute of'Ohemioal Phyaica, and T.n.nmTjnar, {toysioal-Xechnical loidemy of Belnera of the US8B, llosoov B-»4, USSR Institute of the Academy of Soianoaa, Karen 420029, OSSB A «pin wave damping mechanism is proposed implying tempera- Magnetic properties of a nnnl paramagnetic metal in m ture indapandent IUB llnewidth Aid observed in some pure me- galvanic contact with ferromagnst era of current pbjaioal inte- tals I /V* Xhe "s-d-ezohange" interaction between spin waves and rest, partly motivated by the possibility of electrons polsriia- conductivity electrons /2/ has btcn investigated; This Interac- tion dua to a natural or foroed diffuaion of tha oarriara from tion does not contribute to the 1KB llnewioth in second order a ferromagnetic sub-layer /1,2/* Correct deaoription of such a perturbation theory because of the prohibition, imposed by con- system necessitates the knowledge of the eleotron scattering pro- serration laws* Ihus the "a-d-exchauge* contribution is deter- bability an the boundary with and without a apis-flip* The pur- f mined by corrections of higer order (for example, due to elec- pose of this report is to study a restricted task whan the thide- tron-phonon interaction). Such corrections have early been in- neas of a ferromagnetic aub-layer ia negligible, so the condi- cluded in the theory by taking into account the finite wiatb of tions of the experiment correspond to a simple model of surface electron energy states /5/ This aprmtinmtion, leads so the tem- relaxation with a good probability of spin scattering on the a peracure dependent A CO . boundary* measurements were performed via the STB method in the X-band over the temperature range 100 to 400 K on the lithium It is shown here however that besides the flute widen of films (with the thickness d>o.7*4.2/un) with an invar sub-layer electron states tne "deformation" of the "s-d-exchange" poten- (< 5oi). The samples were prepared by evaporation in vaeuum tial due co electron-phonoa interaction Bhould. be takan into 5*10~^Torr in one pumping act* In the case of strong surface account, account of thfc, circuBstance leads to specific expres- scattering when/*:»•/. a new type of spin relaxation with the sion for the spin wave damping decrements oTK) ^C K aize and temperature dependencies of the relaxation time Tfdtd {K is the wave vector of the spin vavef ^T is the moan free was discovered (0-the diffusion coefficient, A-the mesn free path £or electrons). Because cf the skin en'ot the B? magnetic 2 path,o!=«2.5). for a weaker "Bpin-orbit" Boatterer (niobium) we field exites spin waves with/C*~6"" ~6" (5" is the skin succeeded to observe a step-by-step transition fromjhs case^of depth, 6" Is the conductivity), i.e.A60~tr"^(T • Sincefr^-T , strong relaxation to a well-known Dyson relaxation^ — £l£rf /3/ we obtain that A

~~^. Hilnrlch. B.F Kaaborsky V-jPraitova D.,Kiya,St!it.Sol.,i~~

~~C323 MAGNETIC STRUCTURE AND INTERNAL FIELDS IN ND, (CHj) iNDjCuCl,,~~

~~H. Rammer, Laboratorium fUr PestkQrperphysik, ETH-Hdnggerberg CH-8093 ZUrich, Switzerland~~

~~EthyXene-diammonium-copper-tetrachloride is a monocllnic layer structure compound with space group P2,/b and Z=2. Chlorine octa-~~

hedral planes are bonded by ND, (CH2) 2ND,-chains. The paramagnetic Cu -ions are located in the centers of the chlorine-octahedra. By deuteron-NMR and by magnetization n.easureraents the magnetic structure below the Neel-point T =(34+l)K was determined unarabi- 2+ "* guously: The Cu -spins are ordered ferromagnetically in each layer plane along the monoclinic c-axis and antiferromagnetirally between adjactent planes.

doubling of the magnetic unit cell below T gives rise to a symmetrical splitting of each of the 12 paramagnetic deuteron-linea owing to six physically inequivalent sites. From the difference between the paramagnetic and the two corresponding antizerromag- netic lines (see figure) the component of the internal field

along the HQ-direction can be obtained. Measurements below and above the spin-flop-field (9 kOe) were performed. Calculations of the dipolar fields caused by the Cu2t-splns (Prfj do not agree with the mea-

~~sured fields (Hcalc=400 Oe, Hmeas =l0° •" 20° Oe)' This difference is probably due to hyperfine contributions from neighbouring chlorine-atoms showing a z°" «• «r «• txf ac mr~~

Figure; Part of a D-NMR-rotation pattern;fl *& kOe, rot.axis [Olli C330X- CJ302 CRITICAL AND HIGH-TOHPERATURE SPIN RELAXATION IN TOO INTERACTION OP LIOHT WITH THE SPIN SYSTEM AT THE. 3-DIMESSIONAL AND TWO PLANAR FERROHAGNETS FERROMAGNETIC RESONANCE IN KjCuP,, A.5. BOROVTK-P.OKANOV, V.C. JOTIKOV, U.K. KREIHE5 and W.L.C.ROTTEN and J.C.VERSTELLE, Kamerlingh Onnes Laboratory. V. ZAVARITSKII, Institute for Physical Problems, Academy ' University of Leiden. The Netherlands of Sciences, Moscow, USSR, and R. LAIHO. W!huri Physical Laboratory, University -.r Several theoretical predictions have been made for the cri- Turku, Turku, Finland tical part of the uniform relaxation rate (or characteristic frequency, linewidth) in lero static field in [erramagnets (Kawasaki. Ferromacneti c resonance was excited in K-^'uF^ and irive3tif-r- Haleev, Huber, ds Baas). Unfortunately, most experiments up till teelow catai-atii i

~~Cu(NH4)2Br4.2H20 (3-dimensional ferromagnets) and the planar fer-~~

~~romaonets CulCB3KR3>2Cl4 and CulCjHjSHjljCl^ . They have been investigated in the easy direction as well as in next preferred axis and hard direction. The entire temperature range from~~

TQ - 300K was covered, which revealed the absence of a constant high-temperature rate in all the compounds. Also a parallel static field up *.o 35 kOe was applied. All data are ahape independent by incorporation of denagnetizing effects. To be as accurate as possible, we used oar own Btatic susceptibility measurements, performed on the same samples. All the compounds show 7/3 a approximately the theoretical c" dependence of (X r*r)crlt , with a - x,y,2 , in the "exchange region". For in > 1 In the o planar salts (X r£r> becomes constant, while in CuKb and CuNH4 an e~Z^3 behaviour can be observed (the "Dl" region of Maleev /!/) and ultimately a constant value at about e = .001 CADI" region). In all the compounds anti-symmetric exchange is possible. He discuss the influence on the relaxation especially at "very" high temperatures.

~~1. Haleev,S.V. Sov. Phys. - JSTP, Vol. 42, No. 4, p. 713.~~

4 C3303 C3301 FSEBDlUaiBTIC BBSOBiSCB LIBS BDMBSIBG HI CUBIC HVESTKUTIOB OF HEIACOHAi FEHHITBS NigScW EX FMR ISBBOMaQBSTICS DOS 3D SOUIH STBUCHIRE METHOD THROUGHOUT TEE TEHPEEATUHS RANGE 300-*,at V.7.D1HIL0V, I.T.ZATIStTJg. and T.I.SUGADV, Eler State T.I.IVABOVA, L.X.KOLFAKOVA, I.I.PBTROVA, T.l.SMIRKOVA and Dooiversitj, liar 253)17, OSES. H.T.CHEKP.AK, Institute or RadiophyBica and SlectronicB sf the Ukrainian Academy of Sciences, Kharkov JIOO85, BSSR •» MchaniBB of lerromagnetic rawstnca lisa broadening is proposed for fenoaagBetica with periodic doaaln atructare. The Establishment of interrelation between the magnetic ciya- aotmnifnTltj of '• staple ugnetizatlon due to domals atruettire tallographyc aniBotropy, spin regulation and cation distribution 1* aboan to onu tkc alxins of uniform pnusaian with apm in such complex ferromagnetics aa hexagonal ferrites is an Im- •an at l-^p-. wbar* n is an iotagtr, Ztt is the period portant problem in studying of magnetic interaction nature. It is of doBain structure. Ibis aixiag xaaolta in the exultation of possible to affect exchange interaction ky dimensional change of

not onlj nalfoim aoda but also of associated spin ware* at unit cell or by its deformation. In the Bi2W syBtem this wae per- saaxlT tne eaaa frequracj tgr aeans of onifoxa u.h.f. wagmtie formed by injection of So cations which have the large ionic ra-

f laid. Xharef oxa tba lisa of unif on» aode should ham jaaks dius ( zt =0.83 i) /i/. eoixaapoBUaK to tha axeltatian of spin wans propagating aloBB A new system of BaBipSo tba sxtanal da aagnatic field with 4-^L . Q, irtensitj Fa^g^O^n compounds with zs0*2 of tha paaka is the lower tba anra aoT» tnalr fxagonwlaa away was investigated by FUR method in fzom thoaa of tba tmtfozai aoda. In real a/ateas tha peaks axe the temperature range 300-4,2 K. apzaad Ana to aoaldaal doaain nhruetiira and tba presence of Anisotrofy field Ha, intensity and nViaaina lead* to unlfoza prasasaiun lisa teoadamng. linewidth of FME ware measured on in the work the valna of tba fasmaagaatie raaonaaoa lisa ths polyerystallle spheres broadening of b.f.' uniform and* [i, 2] is conaUezad fox cable $< 0.7 ran with a high degree of ferromagnetics with negative aMsatrasT depending on doaain texture within the range 30 to 70 atrmtura paraaatan. SM lisa hpoadaning dapanda atronglj on OH*, in external field up to 25rOe tba relations tataaau the period of doaain structure, doaaln was produced by a superconductive wall thiekneaa and tba value of spin war* factor. IS 2.0 X magnet with the ferromagnetic Ihe numerical estimation* of tha broadening are prasasted. In tha Jig. ths dependence Ba on 3c3* ion concentration la 1. Artmaa, 3. Phjs.Hav., jD5, 6a (I957i. given for temperatures J00 K and 4,2 K. Anomalous behaviour of 2. Etror, C.I., PilshonlioT, 1.1., Syrjev, H,S. fis.Trerd.Tola, Ba at a large diamagnatlo dilution (x> 1,2) ia causad by distur- 16, 3051 CI97*). bance of tha eolllnaar apln regulation due to reduction of tha 5 indirect erohange Interaction *fTi-Z*-«fTl whan "a * iona is substituted by 3

~~I. Si«ov,H.A., Orom»ln,D.E., ZaItoev,K.»,, Ivanova.V.I. Zh. Bksp. fcor.wia. 66, 2195 W975). V~~

C330S " " '-' C3306 GEBXRALUBD WICK'S THEOREM (OS SFII 0H81T0RS ISO BWBCT or IOIS WITH MHORITX VAUJTCE OI MAMITIC ABISOTBOPY AID REXAIATIOI ITS 1PPLIOAIIOI3 TO THE THEORY 07 MAMMISH A.0.6UHBVICH. L.U.BCmH, K.O.sIKIMROV and A.N.ANISIMOV, Y.p.amSHHIKOT. Institute of Metal Inysios Academy of Seiencaa A.J.Ioffa Physico-Teohnical Institute, Academy of Seienoes or the USSR. Svardlovek 620219. 0 3 S B. USSR, Leningrad 194021, USSR A aet of quantum langavin equations for tbt Fourier compo- The role of "fast-relaxing" ions governing magnetic aniso- nent a of apln density of a magnetic sjateit Is derived via the tropy and dissipation of magnetic osoUlstlon snd spin wavss in uonequilibrium statistical operator technique in the fora out- •form- or farrfjugnsts can bs played by Ions of the same slexnnts lined In /1/. The formal solution of theae eqa oonaista of two that form the main magnetic systsm but with another (minority) terms, the first of which describee the evolution of the spin valence. The riss of nuoh ions can be stlmulatsd by doping with operatore according to macroscopic law whereaa the second cor- some other (e.g. nonmagnetic) ions or by vaoanoea. The peculiari- responds to the fluctuations of the true nechanioel trajectory ty of this case is that the interaction between these ions and with reapect to the macroscopic notion of nonequilibrlum average the ions of main magnetic system or the stimulating centres can density of spins. The nacrosoopic notion results from the repla- result in complicated M-ture of the effective centres governing cement of the exact mechanical resolvent operator by the matrix magnetic anisotropy and relaxation. Green function /2/ of a sst of coupled linesr equations deecrl- Experimental data are presentsd on the influence of cr ions bing the aimultsneoua relaxation toward equilibrium of the spin with minority valences 2 and 4 on the ferromagnetic resonance in averages. Thio representation leads to tht perturbation theory CdCr.Ss, and CdCr-S, crystals as wall ss on ths damping of spin for ths aultispin time correlation functions in which the tero- wavss with wava numbers k . 10* - 106 cm"1 determined fcy measu- order approximation lnvolvea the maoroacoplc motion of spins only ring the thresholds of parametric excitation of epin wavos. and the dynamics of spin psir correlations (unknown generally) Cr2+ ions appsar dus to ohalcogsn vaosnosa In CdCr^Ss^ or accounted rigorously. In such B way one can evaluate apin corre- CdCr2S, or due to the doping of these crystals with trivalant lation functions approximately in terms of the exact spectrum of lona (e.g. 0d3+) substituting for Cd2*. These Ions result in the the spin exitatlona which depends on the temperature or, in morn angular and temperature dependences of the field for resonance general caaef on the set of nonequilibrium oacroverlables descri- K and resonance linewidth AH consistent with the theory of bing the state of a system. The zero-order approximation, la "slow relaxation11. Cr*+ ions that an stimulated by. the doping which stochastic forces In the right hand side of the langevln with monovalent ions (e.g. Ag+) give rise, In the case of ' equations are neglected, is considered in detail! and its connec- CdCr-Ss., to HM> and AH angular and temperature depemdeacea tion with the mode-mode coupling theory is shown. In ths ssme ap- also consistent with slow-relaxation aeohaniam but with tha near proximation a simple procedure /3/ is developed for calculation crossings of lowsst energy levels in another direct lone. However of the multiapin correlators in terms of the spin pair Green fun- in the case of CdCrjS. some peculiarities have bsen observed: ction spectrum (generalised wick's theorem). The results are AH maxima not acoompanisd by maxima in Hni and anomalously applied to the description of tne dynamic behaviour of the Eai- ateep AH temperature dependences. senberg ferromagnat and the s-d system. Ths raat-relaiing Ions with minority valence (as wsl_V as the impurity fast-relaxing ions) lssA to she spin-wave aampinf 1. Zubarev, D.H. and Kalssbnlkov, V.;. Teor.aat.piz. 3, 126 (1970). that depends weakly on k up to sons'k values (of the order 10r 2. Hori, H. Progr. Thsor. Bhys. 33, 423 (1965), 34, 399 (1965)- cm"1) snd then begins to grow rapidly. 3. Kalaahnikov, V.p. Doka.Aksd.Nauk 3S5R, 239, n 5 (1978).

C3307 0 jL^,- CJ308 QUANTITATIVE ANALYSIS OF HAGNETOSTATIC EXCITATIONS IN THE ' EPR STUDY OF SOIE FERRIHAGNETIC CONFOUNDS CUC1 FERROMAGNETIC LAYER COMPOUND (CJHJHHJ) 2 4 - r>, HAGDA BALANESCD and I.DRSD, National Center of H.REIHAHM. H.HAGEN. F.HALDNZR and H.AHEHD". Institute of Physics. Physics, P.O.Box 5206, Bucharest, Romania University of zOrich. CH-8001 Zurich, SWITZERLAND

~~Hagnetostatic modes of an isotropic ferromagnetic plate of infi- He report the results of psrsmsgnetic resonsnoa aassuremsnte~~

~~nite extent have been calculated by Dsjeon and Eshbach (OE) /I/ on OdlCo^Nlj.^lj snd GdHlt(s - 3/2, 5/2 and 17/2) compounds .Below~~

~~and have been expecimentally verified in TIG , a compound with Curia tempsrstnra, Te, these systems are ferrlmagnetleally ordered.~~

isotropic g-factor and only a weak cubic magnetic anisotropy. The In GdfCo ni^_x)2 compounds'. Ml Is not magnstlc, vhUt the asenstlc extension of the theory to anisotxopic media ia straightforward moment of cobalt atom Is dependent on the local environment / 1 /. since the DB-foimula, expressed in terms of the permeability tensor The moan magnetic moment of nickel atom in *JNlr system is function only assumes u^.+u.^^o for the off-disgonal elements. However, on ooaposltion / 2 /. By' rseonsnos studies at I » Tc wa analyse ccEipounds with a strong magnetic anisotropy have not been avail- tha Influence of transition metal content on tha g values and on able until the realization of magnetic low dimensional systems. tha linewidth.. ' . Tha effective g values increase with temperature from a mi- we have investigated the layered copper compounds of the chlor- nimum value located at a teapersturen T + 20. The experimental ide perovskite family with conventional ESR-techniques at 4.2 K c data ware analysed using a aodsl where g values arm dependent on and 9 GH2 and found spectra of well resolved magnetostatic modes tha type of atoaa of tha two sublattioas and also on their msgna - /2/. The dispersion equation for a reetangulsr platelet is calcu- tic susceptibilities. lated assuming &H( B) The ggj values increase by increasing tha Co (or magnetic Hi) (1. \ (n,.l) (1) snisotropic permeabilities with content. The presence of Co (or Ml atoms breaks the bottensck essy-plsne snisotropy field H •20 a between the conduction electrons and the lattice, providing a path and the measured uniaxial g-ten- where tha conduction electron magnetisation can relax to the lat - 1 sor of the paramagnetic state, tics. The influence of the variable magnetic Interactions on f^ .10 (2) geometrical quantization of the values Is also discussed. The thermal varlaMon of the linewidth in-plane wavevector. ir In agreement with the present mote-. ; The figure ehows the fit of a spectrum measured with the 21 11 1 11 21 31 applied magnetic field parallel 1. E.Burso, D.P.Lailr and H.vlleenu, Phys.stat.Solidl (b) (5, Mode separation va. quantization to the surface. The resulting* KU5 (1974).

psrameters Hg (magnetization) snd Ha are in agreement with other 2. i.Burso and j.Laformst, C.R.Acaa.Scl.Paris , 274B, 114 (1972). measurements, but we emphasize ths fact that the procedure to eliminate the anisotropic g-factor using modifisd fislds is not an alternative treatment.

~~/I/ R.H.Damon and J.B.Einbach, J.Phys.Chsm.Solidr 19.(61)309 . /2/ B.Reimsnn, H.BSgen, F.Waldner, W.Berlingsr and H.Arend. Solid state communications 17.(75)1319 V~~

C3309 C3310 ROTAMSG SAMPLE METHOD OSES HI IERROKAGBETIC Kagnetit.- Resonance In Hickei at High Temperatures. HBSOHAHCB BXPBRIHEHT OS FEHRITE SIHGLE CRYSTALS S. Haraldson and L. Pettersson, Dept. of solid state physics. J.K01OTM,T.ChsjlaB University, Faculty of Mathematics and University of Uppsala, Sweden. Physics, Department of Physics of Metals, Prague, CSSB

1 spherical sample situated la microwave spectrometer with An experimental setup Is described, by which If. 1s possible to high-frequency modulation rotates uniformly about the /110/ heat the sample without heating the cavity. The temperature of direction at the rate of the order of one revolution per minute. the sample is measured during the run of the spectrum. It is The axla of rotation of the sample holder is perpendicular to possible to reach a sample temperature of at least BOO °c with- the magnetic field. The detected sigmJ. is proportional to the first derivative of the absorption curve. The described method out appreciable warming tip of the cavity- can be used for a dlxect measurement of the extreme Talue of the He have used this setup to investigate the resonance at 9.3 GHz resonance magnetic field corresponding to the dependence of in nickel In the temperature Interval 300 - 450 °C. The line- this quantity on the azimuth of the sample in the (110) plane, width appears to have a maximum at around 3"/5 °C. Move this the method Is cased on the Interpretation of the shape of the temperature the linewidth decreases, but not very steeply, and detection curve whose periodical ohancter is a direct consequence reaches a minimum, after which the linewidth stays constant or. ol :£; zct^l^n ana who*' shape depends on the magnetic field. possibly. Increases very slowly. 1,' f- The measurements carries ;

~~C3311 C3312 FLASH* EFFECTS tun MTCHEEOIUCE REGIOB ON THE COMPOSITION DEPENDENCE OF g VALUES IN SOME n tBsauasac cctrajcmns YTTRIUM COMPOUNDS~~

E.BDBla. B.BAXCMI and I.UJBn, National Center of Physic J. CSTLO ; C. HTLMB ; H. BOOTnTKmi ; laboratoire d-Electrcasgnetisae P.O.Box S206, Bucharmst, Romania B.I.S.E.B.a. 23, rue del Martyrs. 3SO31 (KOSgBXE CEDEZ (TRUCE). We report the results of ferromagnetic zeeonance atudiau on *(TiT"l-i'2 compounds, where T', T" • re, Co, Mn or Al. The mea- The electromagnetic fi«M structure in a ferromagnetic cenductiTe piste anrements were made In two fraqneneiem bends (9.3 GBx end 23.4 an), in the temperature range ( 78 - 3OOTK. The experimental data sntaitted to • static magnetic field perpendicular to its plane remlta from may be well described by means of the individual g values of T' the coupling between spin raves sad vnres coming fns the motion of the car- end V" pure mstals s riers (plasma nn «t la, tespersture). We determine at nan and low teaperatures the coupling coefficients of (1) the mm winch are solutions of the dispersion equation. With, this coefficients ve csn study the influence of. each node. Whereas at ferromagnetic resonance no mode can.te neglected, near antiresonance the We noted by M,, and «,. the magnetization of the two sub- spin van mode has little influence on the electromagnetic field structure. lattices and by g^, and gT. Thus we esn give an analytical expression for the surface impedance and ' I*- their apectromcoplc splitting the transmission factor at room and lor temperatures. factors. X——' Thm coapoaltlon depeAuenoe of We explain that near antiresonance region the surface impedance abovs g values in case of a minimum, v&ereas the transmission factor can snow either a — ~-»m or a YfFlgCo^^lj compounds is pre- Talue according to toe thickness of the plate. sentmd for example in figure . By solid line Is plotted the relm - tlon (11 with g^ - 2.20 and gM - 2.12 and B^ and 11^ determined We determine the critical thickness for vkichao singularity can he ooser- from magnetisation amasureamnta / 1 /. Ted. The experimental results obtained with liekel plates justify the pattern Although the mean magnetic mommnt of 3d transition mtal.ln ve propose, at all temperature. these compounds, is modiflmd mm eompmimd to purm mat ale, the resonance measurements mhow thm constancy of g, values. These data are further evidence) en the local environment effects on thm tran - sltion metal meaants as previously suggested / 1, 2 /.

1. X.Bnrao, SoUd State Ccemi. 35, 525 (1978). 2. •.Bum, rhyajmnr. BIT (W78), in press. C3402 m cwoi CRITICAL RELAXATION OF THE SPIN SYSTEM IN KgCuFj EPR AHD HYPOTHESIS OF UNIVERSALITY T.HASHIMOTO, Y.fOJIMA and T.IKEGAHI, Tokyo Institute of V.G.AHTJFRIEY, Institute of Physics, Academy of Sciences of the Technology, Oh-okayama, Meguro, Tokyo, Japan Latvian SSR, Salaspila 229021,USSR In order to clarify the critical relaxation o£ a spin system CuF noar in the two dimensional ferrdmagnet K2 4 Tc(-6-25 K)/l/ and The hypothesis of universality (1] suggests, that all sys- also to compare this result with that in an ideal three dimension- tems with equal dimensionality d and numbers of freedom degrees al ferromagnet EuS /2/, we have measured the frequency dependence n of the fluctuations of the order parameter have similar criti- CuF over of the high, frequency magnetic susceptibility x(u) of K2 4 cal behaviour near the phase transition temperature T . The hy- c the frequency range from 1 to 250 tfflz in the temperature range pothesis of universality is applied to the EPR spectroscopy in from 6 to 7 K. the present work. He studied the systems with d» 3 and n» 3,

~~namely ferroaagnet Cr2(Cr04)3 , antiferromagnet Cr^Oj and solid Recently several interesting works on the critical spin re-~~

solution (Z-x)Cr2O3 - xaFe2O3 to.20 Sx SO.35) with weak ferromag- laxation have been carried out by means of the high frequency magnetic properties. It was found, that EPR in these systems with netic susceptibility measurement. In such study we have to bake different kinds of the magnetic ordering could be satisfactorily into sccount the correction for the demagnetization field de- d*k«erlb*d in the terms of one model. The basic process of magnet- pending on the sample shape, because the magnetic susceptibility

~~ic •Mrgy transfer in the paramagnetic phase (T»Tc) was found increases enormously in the 3+ tg fc* fcfc* pbonon modulation of exchange interactions between Cr vicinity of Tc. Hawever, it~~

iou, sad tin BPR linewidth near Tc was governed by singularity is very difficult to make a of tfas static magnetic susceptibility and the correlation length precise correction for the in the phase transition point. The values of the critical index demagnetization in the usual of thai BPR linewidth broadening near T (AH ~ l-r^j'*) were measuring method using the found to be K - 0.61+ 0.10, 0.15 + 0.03 and 0.30+0.06 respective- spheroid sample. In order to ly. It was Shown that the values of critical indices given by the avoid this difficulty, we modern theories (2.31 could not be used in. the temperature region have used a coaxially shaped

~~somewhat above Tc where we found the critical broadening of the sample. EPR line in these systems. It was suggested that magnetic phase The frequency dependence of x("> observed in the reduced tem-~~

transition in CTJOJ had some features of the structure phase perature region. e«(T -Tc)/Tc > 3 x 10" , was consistent with the transition, which could be destroyed by doping Cr2O3 with F.3e + Debye type dispersion model, while, in the temperature region ions. This has been confirmed by the EPR spectra analysis of E<3xlO~3 the value of xtw) in the frequency range lower than

(I-x)Cr2O3 - xoFe203 US 0,15) system. 3 MHz grew up and deviated from that expected by the Debye model. The Cole-Cole plots of xtu) in Figure clearly show this devia'tior. 1. Kadanoff/ L.P. Critical phenomena. Proc. Int. School Phys. The critical index of the relaxation time was 1.10 ±0.05. the val- "Enrico Fermi"/ Academic press, 1971 ue which was smaller than that of the static susceptibility >g, 2. Kawasaki. K. Phys.Letters, 26A, 543 (1968) 1.36 ±0.01. The detailed frequency dependence of x^l °f *• &&* 3. Huber. D.L. Phys. Rev. B6, 3180 (1972) and the critical index will be shewn and discussed.

~~1. Hashimoto.T. and Sato,A., J.Phys. Soc .Japan 38, 345 (1975). 2. Shiino.H. and Hashimoto,T., to be published in J.Phys.Soc.Japai..~~

C3103 C3H04 FiBUUGBXIC BEEOHAHCE IN aUGSECIC SBCCOltDOCTOHS EXPERIMENTAL PROOF OF SPIN DIFFUSION IN THE QUASI- T.B.BRHzajWfT- 7.1.171107, S.A.IIAVBICHKOV. L.7.Kirenaky TW0DIMENSI0NAL HEISENBERE PARAMAGNET (CjHjN Institute of Physics, VBSd Academy of Sciences, Siberian H. BENNER, Institut far FestkSrperphysik, Technische Branch, Krasnoyarsk 66OO36, DSHB. Hochschule Darmstadt, D-6100 Darmstadt, Federal Republic of Germany A rosy weak aagnetlo anisotropy, an existence of only one magnetic snblattioe and possibility to change the density of High temperature spin dynamics in the quasi-twodimensianal ' carriers make the ferromagnetic ssartenndactor CdCr^Sc^ an ideal Heisenberg system ethylammonium-manganesechloride have been invv'rigated by EPR. Two different experimental methoda are object fox atudy oritical dynamics. Critical (T=I0> and spln- pit fitted -which can be UBed to analyze the reaonanees of phenon relaxation processes (T>TC) are Investigated In CdCrjBa crjstsls with various p and n-type carrier density and also in the respective memory spectrum occurring -at* the taraor frequency (Up and at 2

C3105 C3M06 BUB SIGJAZ, BSLAXATIOlf IB THS VIC1S1TT OF TBS FTBflf , IBTHUCTIOHS IS . 5 OBHER aPm-BBORHETATIOH PRASE TSAH8ITION OF THE HOBIH COkPiBSS OF 3d -I0SS WITH CIOSB LBVELS TTH! HI BARS ""T" OBTHOFEBBITES OF DIFFERENT S?IK MULTIPLICITY. T.G.BABIAIHTAB.Tffs.KAMACHE?, H.M.KOTO1H, T.K.SOBOLEVA, T.samiiOT. Y.ZBLMTSOT, V.PBDiaKO, Moscow Fhyaico-Teehnl- E.B.SOLCY'EY. AND E.P.STKFAKOVSKII, Fhyalco-Tochuical cal Inatituta, Moacow 1*1700, USSB. Institute of tha Ukrainian Academy of Sciences! Donetsk, 340048, USSR. In some complexes of thioaamicarbaunataa of Fe(iii) the llgand orystal field la so largo that energy difference of dif- Temperature dependence of the transverse relaxation tine ferent apin multiplicity electron levels is comparable with kT. of tna nuclear magnetic resonance (HMH) signal on Fa" nuc- In this case low spin-high Bpin phase transitions ara obsarvad. lei in rare-earth orthoferrites in the vicinity of the first Those phase transitions ara reflected by sharp changsa in magne- order spin-reorientation phase transition of the Morin typa was tic susceptibility and SSR spectra IM. Investigated both theoretically and experimentally. As high spin state affective ion radiua la larger than the Dv Co Measurements of time ?2 were carried out in *»o.998 O.OG2 low spin one ligands' adiabatic potential as a function of all- 0- wi£a the help of an automatic spin-«cho spectrometer using aymmetry local normal coordinate has two nonequivalant y^nm ths double pulse technique. The figure presented hare shows ex- which ara separated by the potential barrier. Low spin and high perimental temperature depen- apin electron texna forming the potential make up NanticroBBingn dence of the time T2 In the due to spin-orbit interaction with higher eneigy levels. Account vicinity of spin-reorlentar mast be taken of the thermal equilibrium between rlbr.itii.nal tlon (notation is the figure* states of both adiabatic potential minima, aa distinct tram Van- 3W AF AF is tha antiferromagnetic Heck modal of paramagaatism wich includes only electron atatee phase, IF is the weak ferro- Boltsman population. Van-der-VaalB attractive forces give rise magnetic pbaae, T=I40*E in to twin Interaction potential governing paramagnetic ion atatea W the transition temperature). correlation. For theoretical descrip- Suggested cooperative interaction mechanism is covered by tion of the obtained results the hamiltonlan of Ising modal an as no IK a two-sublattlce modal of rare-earth orthoferrites la n i i a " ^ used, the account la taken of tb« presence of the domain structure of rare-earth orthofer- whare Bo ia electron part; H, iscludea asymmetric parts of elec- rltes Is wV-phase end of transient domain structure in the vici- tron enargr and cooperative interactions; I,, ia symmetric part nity of the spln-rearientation transition point. Theoretical of cooperative interaotiojue determinedtby Van-der-vaala forces results axe in.good qualitative and quantitative agreement with and electren-phonon contribution^is tunnelling frequency; Sis the experiment. paaudcjsiln with eigenvalues corresponding to the system locali- sation is Una of tha adiabatie potential "^"*"» Solutions of elQctroa-vlbrational problem (1) predict experimental data. t. shlpllov, Y.I.. Zelsntsov, V.V., Zhdanov, V.M., Turdakin.V.A. JBTT letters 19, 560 (1974).

C3107 C3408 •AIHKTTC BXSOIAICB II IHE lIO-DIlDa3I0IAL ISIIC KiSIET BUR IN THE SYSTEMS WITH UGHBnC ORDER G.OaBBnlH, A>R«V»WWT. Kaxan Fhyaico-technical V.V.PRUDHIKOV, r-a-Tf!TTBT.i>flM Eazan Thysico-Tecfanicsl Inatituta of the Academy of Sclencies of the DS3B, 420029, Institute of the Academy of Sciences of the USSR, Kasan Kazana USSR. The theory of BMR in the systems with highly developed mag- The rigorous theory is developed of the magnetic resonance (MR) netic fluctuations, which take place under phase transitions, is In the two-diaensional Ising modal that is the nontrivial many considered. The nuclear spin relaxation due to hyperfine inter- particle system with the phase transition of tba second order- action of electron and nuclear spins is investigated, because it It la anown that in'this model there are fin resonance linea at most apparently exhibits all peculiarities, caused by phase transitions in electron system. the frequencies Jl=\u>^-mJf!\, where u>o is the Zeemaa frequency, 3 Is tits exchange.integral between spine, m«0,±1,±2. The effects, we study, may be divided in two parts. The first tske place in HMR' of two-dimensional dsgenerate magnets the iateoslty JiiSL^} of a resonance lisa at tne frequengy SLZ increases monoônically with tha temperature decreasing and reach (IY and ileiaenberg models) nt low temperatures. It is well kno- a waviwnwi at I • 0 . All ether lines have the absorption maxima wn /1/, that the corresponding phase transitions are rather pe- culiar - the spontaneous magnetization is absent, but there ap- at certain temperature Tm> Tc (Tc is the phase transition temperature) and vanish when T — 0 . pears a new quantity "stiffness", which is an analog of super- The m llneehape due to the dlpole-dlpole interaction between fluid density of liquid helium. This gives riBe to unusual beha- the •sins is considered. Tha temperature dependence of the width viour of BUR llnewidth. For example, its dependence on magnetic and smlf t of the MR Unas Is investigated, it la shown that the field h is given by nonuniversal law Ieinf szohangs reducea tha MH llnawidth taut the character of narrowing strongly differanta from "that in the case of Hoiasnberg iu exchange. The simple physicsl interpretation of theoretical re- where t = T/*^^ 7" - is the temperature, C7 - is the sults im givwn* exchange integral. Ths data of the resonance experiments on the two-dimensional The second group of effects refers to three-dimensional Ieing magnet FaCl^ /I/ ara explained. systems. Here the MMR linewidth has the next temperature depen- Is tha figure ths solid curve marks the dence near the critical temperature Tc experimental temperature dependence of the MR line integral Intensity at the frequency d , tha dashed lisa Is ths o y is the exponent of correlation length, T-(T-Tt)/Te. The va- theoretics! curve following from our luee of dynamic critical exponent Z in different systems tbsory* As ess, be seen from the figure, are discussed. The crossover of the temperature dependence of our theoretical curve gives the correct Su from exchange to dipolsr regime is studied by £ - ex- qualitative description of tbs experi- pansion mQthod. ment for the whole temperature range in 0 10 iO Tc TK coatrsst to tha theoretical results,, ob- 1. V.L.Ber*zinsky, Zh. Exp. i Teor. Fiz. 59, 907 (1970). tained in the spin-daster approximation IM (tha dete-assbad curve in the figure) IM Bate sl>, Matskaws M., J.Appl.Phys. 22, 820, 19&B . D311 D312 »ot mmuxaua, IKBOTIC wmen a Tin 'H-.^C- in 17o-nanric RISOHAHCE aUULmUSXtS SI ZiXQJJZSB • 8VBUTVA OF mm N0LICDLI8 Dl ACXTOIQE* A.I JBWaHW ml B.I.mgn. Institute, of Ohealaal Kinatiaa Q.liagOTT.II.I.gnlJ..lruKer-fhvaU AO,D751I Xaxlaraba-Mialnatatten, nl Ooabastian, the USSR 10*007 of Baienaes, Blbarlan no, and ».A.SCHIjmAXOV,V.a.Khlopln Udlum Znatitute of SIM, Brenoh, Bbvoslblnk 630090. SB8B.' Laalnjred 197022,D8S» * 12 S» impact theory daaorlbae a.uellte*lvely m'-l the oollapae The greet variety of poaalbla water spectra on the nuclei B,*H, ot the rotational struoture during gte-uqnid condensation /1,2/. 3B and 170 exhibit Interesting isotoplo eflecte,which have not 1 Vsuelly th* relation batmen orient atlonal, Tt, ul rotational, been aeaaored with aufficlent acouracy.We have" sjeaaurad the H-, fj , relaxation tlaaa aaaaurod by tha MR technique oan ba ve- 13C- and 170-apeetxa of 28.15%-nO-enrlched HjO In different rified experimentally. It haa been found that tba Hubbard rela- aolvanta at variable teaDjaratnza and different frequenciea up to tion T»-Jy.i ^£47 (I la an lnaxtlm moment, I la teaperature), 3fio MHi(yielding Bora accurate and new informatlon.Tha 360 HBs 17 whioh results from the theory, bold* la liquids. This fact, how- proton apeetra of aeatone-d6 and B2 0-aolatlon in eeetene-de ever, cannot aam aa proof of tbe theory, alnoa the Hubbard re- exhibit 2.11 BS for tbe 'B-â-coopllng from tha C'Bj1 H-qulntett lation la compatible both with the gesllx* and tho aoUdllka oC acetone^, and 0.91 Ha for tha 'H-'H-COUPIIOJ in 'B2HO/1/. models of orientatlonal relaxation. Msarlmlnatlan batman them Thla laada to the aatiaationa of tha coupling constant^ of oan be done only on the basia of devlatlona from Mi relation 6.93 Ha far 1H-3H em! 0.97 Hi far 2H-3B.T6e pxotoo Isotoplc ahift which ace specific, for aash eodal. due to deuterlu« for acetone 0.036 ppm le determined, by the In thia paper, In the Impact »xn"— ••—*<«n, the first oox- • diataoee between ^^^B-aulntett and tha CHj-elnjlett,which 17 notion to the Bobbard relation In •"«™«, and thoa Includes both the' aorden extended dltfaaiav (J".O) in the proton epectra.The line ahape of tha H,-0-line corraa- an* the langerla relaxation fit «oei>rdinr to Bobbard (f-1) aa ponda well to tbe calculated eextatt,which le broadened by the opposite Halting oeaaa. In coordinates £-7^*; £* thaae differ ouadrupolar moaant of tha 170-nucleu. end aolvatatôn affacta. from eaeh other by alopaa of the asyaptotlo etralxht Uaea wnloh, The 1H-17O-coupllng of 74 Ha waa calculated from the unreaolved la principle, allows one to distinguish between thus, for this aaztett and agraee with our meaauraments of tha 17o-»pectri end purpose BIB data nut be combined with Baaaa aeatterlng which literature data/2/.The CO-region of the 9O.S2 HHi-13C-apectra rtmt\ mm IM)I M frti»i» HWHIWWW of T> •eBaurasetttSa Zhla la exhibit* two well reaolved llnaa arlaing from the 17O-exehanga naaeaaary aapeolally as the blnexttj la partlele eolllaions, between Hj O and tha carbooyl-aToup of acetone-dg with an carbon ehloh is present- In all Tersions oT .the impact theory, aeema to iaotopic ahlft due to oxygen of -0.20 ppm.From an additional be donbtfal for the condanaa phase. Bolldllke modele of orlen- tctlonal relaxation Is liSiiij must differ^fxom gaallka ones by the aayaptotlo beharlour of the function 4, (Tfj which oan "^ osed 1. Holaaa J.F..,Klv*laon 0. and Drincard H.c. J.chem.Phyi.37,150 to disorlBlBate betsei (1962) 1. Gordon,B.a. J.Chea.Fhjs. 45, 16*9 (1966) 2. Eauben J.,Taalnona A. and Samuel DV proc.chem.Soc.353(1962) 2. Barshteln.i.I. end Temtln.B.I. Zh.&sp.Iear.Iis. 71,936(1976) 3. Hnbbard.F.S. Ihys.Bev. 81, 1439 (197J)

D313 D3W M0LKSLU HOTICB AHD IHTB1M0LJSCOIJ& IHTKRACHCKS HI SOLUTIONS OF AlOB ALIPHATIC ALCOHOLS, FATTX AC13S ADD l.THSHS IN EnCl( O.F.BBlnnnOV, A.KOT^OV and B.P.81X01**7, Leningrad State IP.tD.BlMiCT aad B.B.8ABBB0T, lasaa State ualveraity, . Onlverelty, Uningrad 199164, 0S6R Zawa 42000B, m

Some raaulta of the etudy of a number of aolutiona of ali- leaperetnre dependence of the lencltwdlel time f, of tha phatic alcohol*, fatty acida and athera in the Lewis acid SnCl4 I equatorlel protoaa at aethylems ( K aad %') ant aeth- 13 £ by the apln-echo and 'H and C tT-Vm apactrooatry in a wide yl* ( OBJ am* Cm£ ) aave been etndled la 2.2-dlsjethyl-propandlol- range of teaperaturaa are presented. Concentration and te«p*r- 1.3-eeltlte (1) the aeloeules of emieh have beem knoen /I/ are la etuxa dependence of the ealf-dlffuelon coefficient!, apln-lattlce rlcU ohair ooaforaation. Be ratio ot the tlaee' CX * /!,_ la relaxation tlaea and chemical ehlfta of 'H end13 C nuclei were w about 0.9 la the lavastl«eted ranee ot laaujaialuie. . » ~ "B •eaaured in binary and ternary mixtiiree with SnCl and CFClj. 4 tola ratio mast be ssual to 0.5 la ocas of only dipole-dipola In the binary mixturaa we found a atrong decrease of tranalatlan- lateraetlea batveea 1 ami B,, Beaae, -cm a».- aaiuas a oeaalderable al and rotational motlona which wee reflected in deep v-typa A oontrlbutloa lmto relaxation ot iaotherma of eelf-diffusion and T,. atuichioaatry of the minima correaponded to definite compounds. The correlation timaa of ro- the laieraalaemlar dlpole-dlpole tational motion of different aegmanta of the chains of the mole- lateraetione, Ba activation amerfy for 9ffi emd f.- equal culea revealed a gradient of mobility from the terminal methyl : group to the polar and group. Tha beh»7lour of % and13 C chemi- to I^TJO.H keel/mole aad thia ' cal ahlfta waa coapared with the peculiarities in the aalf- vmlae la related to the rotatlo- dtffuslon and relaxation times. At teaperaturea lower than -50°C, sal metlon overall aolseular tua- alow-exchange spectra were obtained with different signals for blia*. A anslisaar dapenaease of the bulk and bound donors. Lifetimes and the activation energy of tta la *1flB* end la *]aa* versus 3 exchange were determined. 10 /!* lmdloatas the oaaqilieated okareoter of tha aotion ot theee •roapa la the aolaemle. Be oor- felatioa tlaa r far the rotatir - aal notlaa at 1 la the oerbone tatraohloride have beam aatlsatted ( V •3.1'1o*12eeo, t*-333 °t ). Be relaxetloa time aeaaaiseeale have been oarrlad out « Bat acintramator BA-100S Tariaa* eenlped by haai aali lapulae enlte tor the eeleotlve ausajrsxaxts of relaxation tlaee, t,, I-, *10 m* tjy , by the reperted aethod IV. 1. SsaMor.1u.la. Bekl. iks*. Ink 8MB. 164. 347 (1965). 2. yreeasaj. emd Wlttekeek.I. 1. amfe. Baa. 1. 238 (1969). D321 D322 PHOTON-EHHANCEO 13C RESONANCE IN 91ECTIC PHA3ES. RUCLEAE Spiff RELAXATION BI IKANSLATIONAX-DIFFUSION IN THERMO- ' OF LIQUID CRYSTALS TROPIC AW) LYOTROPIC LIQUID CRYSTALS WJTH LAYERED STRUCTURE

S.CRAMDE. 3.SCHULZ, and A.LDSCHE S.£uner. PhysicB Department, University of Ljubljana, Jadranaka 1?( Ljubljana, Yugoslavia Saktion Phytlk der Karl-Marx-Uriiveraitlt, Leipzig, DOR H.Vilfan. J,Stefan Institute, University of Ljubljana,Ljubljana, Jugoslavia

Tha liquid crystals undar investigation were alkyl- The theory of the nuclear magnetic relaxation induced by mole- alkoxy banzylidona-aniUna. Lonarifl8 tha teaperature they cular self-diffusion,which has been already developed for isotro- pass through differanc aaactic phiftee* pic liquids /I/ and for nematic liquid crystals /2/J Is extended Th* proton-enhanced high-rmaolutton l3C-WR aavas tiaa to the thermotropic amoctic A and to the lyotropic lamellar pha- in comparison to eingle pulsa aeaeursaentsa All 13c positlona ses in the present communication. Molecular diffusion, which ca- except tha chain carbons in tha longest"aoleculss can ba uses the relaxation via the modulation of the intramolecular in- resolved. In tha ordered phases the line positions in the teractions, is.described by a model, where molecular diffusion spectra depend an the loottopic shift, the shift tensor within the layers is two dimensional liquid like, while the in- anisotropy and tha orientations! order parameter S • In terlayer diffusion is crystal like with a fixed, jump length. By general the shift tenaore are not knowi. but.relative order chooBirs the appropriate rates for intra- and interlayer motion parameters can be determined* Hessureaents gave values of this model can describe molecular diffusion in the thermotropic 5 • 0,7,..0.8 for S end S- phases with only aasll jumps A smectic K as well as in the lyotropic lamellar phases. The effects at the transition points and S - O.9...0.95 for 8 and* . Q of the elongated molecular shape and of the distribution of the S phases connected with larger discontinuities at transition. Q resLaant spine on the spin relaxation are taken into account as From the line collapee a fast rotation of the nolaculea about i well. the.long axis in the eaectic phases can be concluded. Tha

angular dependence in the SA phase reveals an averaged The dispersion-and the oni sot ropy of the spin relaxation rate parallel orientation of the aoleculae. For S^ the dependence can not be expressed in an analytic form to the very end. They is evaluated by the movement or the molecules in the tilted are presented graphically for several relative values of the cone* With increasing angles a broadening of the reaononce characteristic diffusion rates for intra- and interlayer motion. lines is observed. Theoretical predictions are compared to the experimental results for some thenno- and lyotropic phases with the layered structure•

1. H.C.Torrey, Phys.Hev. Q2, 962 (1953); H.Pfeifer, Ann.Phys. 8, 1 (1961). 2. H.Vilfan, fi.Zumer, Proceedings XlXth Congress Ampere, Heidel- berg, p. 1B9 (1976); S.Zumer, M.Vilfan, Phys.Rev. Al£, 424 (197S). ii

~~D323 FORMATION OF DI-TEfft-BOTYLNITROXIDE RADICALS IN LIQUID CRYSTALS By EPR~~

~~G.B.SEDGEEV, V.A.EAIYUlt, K.B.SZEFMIOV and T.I.SHABATINJv, Moscow state University, Hoacow 117234, USSR~~

c. dzred liquid cxyBtalllne structure can alter rate, and direction of cfianical reactions. Chemical stability of liquid crystals is also closely related to the problem. EPR technique jives simultaneously Information about the kinetics of chemical reactions in liquid crystals and the structure of the medium, the orientation order of solutes and the reagent distribution in matrices. The photolysis of 2-nltroso-2-nethylpropane in nematic liquid crystals [in MBBA and in 4-methoxy-4-hexyloxyphenylbenzoate (f^HOPhB)] has been studied. The overall process includes photochemical formation of t-butyl radicals which react with 2-nitraso- 2-methylpropane, giving stable di-t-butylnitL*O]cide radicals. The correlation time for these radicals have been found in order to study the rotational motion in a wide temperature range. It has been found that the reaction rates slowly change with temperature • in lsotropic and solid phases (E = 1.2 kcal/mole). The reaction rate is almost three,times higher in the liquid crystalline phase and increases with decreasing temperature. In other words, we observe a negative tempertture coefficient (E =.-3.5 kcal/mole). The reaction depends greatly-on the chemical nature of liquid crystal. In all three phases o£ MHOPhB slow temperature dependence of photolysis rate (E » 1.9 kcal/mole) was observed. High degree of rotational and translatlonal mobility was found in frozen liquid crystalline solutions. The obtained experimental results of the influence of the liquid crystal medium on reaction rates are compared with the results for the isotroplc solvents. D3301 D3302 SFINECHO STUDY OF SELFDIfFUSIOH IK EXHYIXNE AND XENOH ma BBUxixioi m smnx LIQUIDS, BSUIIOH SBIREH : AT HIGH PRESSURES. TftAHflTiTTflWITi ft1"1 ROTJTTQIij lOXIONS'OI MOUBUJISS.' 0.1. BIVOIaxOY. DepaetamenVoS Jnyaica, lioadar state Bnl.Ttr- B, AREEDS, K.O. PRIMS. H.J. TMPPEHIERS, HOIOOT 117324-USSR. Van der Haals-laboratory, Univaraity of Amsterdam, Valckeaierstraat 67, Amsterdam* The Netherlands. Esaulta of experimental HUB lnvwjlgation of temperature Bad density dependanoe of ttta Impulse and momentum, correlation tinea Proton spinechoas at 2t Hhz have been used in an accurate study of for q,uaey apheziBBl, molaaulea in aimple llquida have Dean analya- the selfdlffusion coefficient 0 in ethylene (C-H^), This investigation ad. covers a wide range of temperature and density. The temperature is varied Ilia Enakog rough bar • aphere nodal unralidity for description hetwaen -150 and 25 °C; the density ranges from 100 to 550 amagat, the of x-elatione beteeen'traaalational and rotational motion ia shorn, latter density corresponding, to a pressure of 3000 bar at -1Q0 °C. aelatiansbip between correlation, timea and correlation function Recently, accurate results of computer calculations (Molecular parameters la discussed. Dynamics) of selfdiffusion In systems of hard sphere molecules have become list available. In these calculations D is obtained as the time integral of the particle velocity autocorrelationfunction; the procedure takes into account correlations In the motion of the molecules, which are lacking in the Hell-known Enskog solutions of the Boltzmaim equation. The so- called "corrected" Enskog results obtained from molecular dynamics provide an excellent description of the density dependence of our high temperature experimental data, except at the lowest densities (< critical density). At the lower temperatures the attractive part of the intermolecular potential causes deviations, from ths hard sphere behaviour. At densities lower than the critical (160 amagat) the hard sphere theory breaks down completely. Very recent molecular dynamics studies in our institute clearly show that the density dependence of D is very sensitive to the shape of Jhe attractive part of the potential. These HD results will be compared with selfdiffusion data in low (tensity Xenon, obtained with a Gill-Heiboom-Carr-Purcell sequeice of Xe129-spinechoes at 75 Hhz. the experimental method, designed to obtain an adequate signal- to-noise ratio will be discussed.

~~"J.P.J. Klchels, B.J. Trappeniers, Physica 90A(197a)17;i~~

D3303 D33(M PROTON SPIN RELAXATION IN CHLOROIWLL-A AND ITS AGGREGATES H0IS0UIA HOTIOH AND NUCLKAE SPIH-IATIICE R.P.H. KCOYMUi AND T.J. SCHAAFSm. Lahoratoiy of Molecular Physics, HEIAIillON IS LIQUID ETHYL BHOHIDE Agricultural Uiiversity, De Dreyen ft, Ifegeningen, The Netherlands. H.UAISIH, Kh.KHYSAIHCIV, V.4BCHD0V l Sa» *f.«*w ^atituta of Chamioal Engineering, tt Spin-lattice relaxationtines Tf have been determined at 100 Mfe for a Tna Kaxan State Pedagogical Institute, Euan, 420021, DSSR lumber of protons attached to the dihydroporphin aacrocycle of chlorophyll-a in its nxnwneric form, its diner /1/ and a diner connected by t» water Tha nroton apin-lattiaa relaxation tinea in aolutlon of atnyl nolccules, the so-called "special pair" /2/. for the nonoDer, there is braaide aSjCBjBr and CD^CHgBr in CDjCD2Br hava bean Beasurad bjr evidence for hindered rotation of at least one nethylgroisi, attached to the •ease of the apin-aoho aathad in vide teapexatuxe range. Bte con- macrocycle. Diffusion constants for reorientation of nononeric chlorophyll are tribution of tne inter- and intramolecular dlpole-dijola interao- D n a 9 found to be :oc" ss S.10 s"\ ILy-2.10 s _w Mhere x and y are two In-plane tiona to the proton spin-lattiea ralaxation of CE, _anl OHWBr groupa inertial axes and z is perpendicular to the molecular frame. The diaer geometry hare bean aeparatad. Rrom the intramolecular contributions the reo- was derived using Ikmtress /3/ formalism by fitting ratio's of experimental rientation timio of the Moleoula aa a whole and of tne internal ro- T,'s to calculated values, varying the relative orientation and mutual distance tation of the aetnyl group hare been eatiaated. It la anon that of the chlorophyll monomers, and is defined by Eulerian angles 4-0-90° and methyl group within aoleeule reorientates markedly slower than the ti|35°. The special pair geometry must be very different from that of the dimer molecule itaelf • Xhia is explained by the high barrier to internal in view of the different values of Tj, but no unambiguous geometry can be rotation. By naana of the BicrowaTe neasuranenta data /I/ thB '°Br determined on the basis of relaxation data alonfi. Further support for the and Br apin-lattiee relaxation tiAaa have been eatiaatad. they 79 proposed geometries cooes from considering ring-current shifts for both types are found to be high short. For exaapla, at U29BS. T]( Br)= 6 8l of aggregates. The results demonstrate that NMR relaxation measurements can be = 1,1* 10" aao and I,( Br) = 1,5 IO"°seo. From the analjois of successfully applied to medium-sized biomolecules (M*2000), yielding important the intermolacular contrj.bu.tl.an to the proton epin-lattioe relaxa- structural information, which is hard to obtain by other methods. tion the effect of the cc—operation in the translation movement of ths molecules have been estimated. 1. Shipman, L.L., Karris, J.R., Katz, J.J., J. Phys. Oiem. 80, 877 C'9'6) 2. Shipman, L.L., Cotton, T.H., Norris, J.R., Katz, J.J., Proc. Natl. Acad. 1. Flanagan.C. and Piarco.L. J.Chem.EhjB. 38, 2963 (1963). Sci., U,S.A. 73, 1791 (19761. 3. Ikmtress, K.T., J. Chem. Phys. 48, 3831 (1968). D3305 D3306 not or cowoncs or mntoxios RADICALS WITH VARIOUS ALCOHOLS HUB HKLAXATIOB1 JS PQLX8TXHBQC SOLIffXOnB E. Dally and H. HUllax-Nareuth, Inatltut.fOr Fhyaikallacha D. GKSOHKB and f. SDEZS, Ssotlcn of Physios "at the Chemle der Dnivarsitat Kunater, W. Cmuiy Karl-Harx-Unlverelty, 701 Lslpslg, SOB

Mtroxide free radicals fora short-lived complaxae with various ID obtain detained lnf orations on mlorodynamlo pro- organic Uganda . The H-bond complex formation la governed by cesses In polystyrene (PS) solutions tha temperature depen- a temperature and concentration dependent equilibrium between dences of tba longitudinal and tha transverse proton relaxa- aaaoclatad and non-aaaoclatad solaoutas ".In •olutlona wltti tion funotlona baa bean investigated /1/. At high concentra- alcohols spin density Is trsnsfarrad from, tha radical to tha tions of FB In dsuterobensene CA50 wt.« minima of proton hydroxyl proton resulting in a contset enitt. In Una broad- spin lattlee relaxation times I1 have been found from which ening, In tha destruction of multiplet etructure and In attxa avenge oorrelatlcr tlaes oould be estimated, the relative relaxation as compared witb other protone. for mathanol, n- (<*10) are explained by a distribution large T1 ^^j propanol, lsopropanoi nd tert-butanol hyperflne coupling 1 of isotropo e rotational notions of the polymer ssrmants. constants between -O,9 and -1,5 HBs have been found wfilch the concentration dependent of tba positions of the depend in detail upon etereospeclflc factora and which vary minima in T., as a f unotion of reeiprooal absolute t'eaperature slightly with temperature, Formation constants of the complex auggeats lnoraaalng contacts between pbenyl groups of tbe poly- have been determined. FroB llnewldtb and relaxation measure- mer obalna with increasing nuabar of aaoroaolecules. ments at varioua frequencies and temperatures tha dipolar and for PS/OgBg solutions In every oase a two-exponential re- ,-1 1 acalar contributions to T, wan d «.T*. have been separated and tha laxation behaviour has been found. Iba 1.,-valuaa of the short time constants of molecular notion as well as the lifetimes of component are comparable «ith those of the system Pa/06D6 and - the complexes have been calculated. The nodal of tumbling > due to the protons of the polymer. The longer ones are asso- rotation with sticking and unsticking of the partners is only ciated with the bensene protons and one can conclude, that a first approximation in order to describe the motion 3'*'. there is only a small magnetic solvens-solute interaction. The nobility of the bensene molecules is more rapid than that of tbe polymer segments (the minima in T., are dateated at lower temperatures) by approximately a faotor of 5 at 50° 0 1) N.A. Sysoevs, A. Yu. Xarmllov and A. L. Buchachenko, and 60 wt. *. Tha results are eoapared with those of Billescu Chan. Physics 15. 321 (19761 and references cited therein et al. obtained by dsuteron BUB relaxation measurements /2/.

2) J. Horlshlma, K. Bndo and T. xoneiava, 1. Geschke, D., Kurze, V., and BrUekner, H. J- Chen. Phys. 58, 3146 (1973) Fsaerforsohung end '.^-tiltechnik/Zeitschr. fur Folymer- 3) K. Mslse, H. MUler-Warmuth and H.H. Hlentiedt, forsohung, In the press. Bar. Bunsengesellsch. physik. Chem. 80, 584 (1976) 2. Srandjean, J., Sillescu, H., and fillenberg, B. llakromol. Chen. 178, 1445 (1977). 4) E. Dally and H. Muller-Warouth. Bar. Bunsengesellsch. physik. chem. 81. 1133 (1977)

DJ307 D3308 mcuuB MAGHSTIC HBLAIATIOB m viscous DYHAMC HUB 0? UOLBCULAP CCS1P1BXS3 19 CRYOGBBIC 30LUIIOIS USHER HIGH PBBSSUBR8 AT 101 TB1FERATURES V.KICSLBH, A.roaTaHg. Donetsk: State Universi- H.S.GOLUBKV. G.S.BBHISOV, Institute of Physics, ty, Donetsk 340055, U S S H Leningrad State University, leningrad 198904, USSB

Fuclear magnetic relaxation and self-diffusion inJD^ft^C The un spectra of liquid systems at temperatures belew (x-Pm-U:) of different molecular weight at - I5O-2OCTC and 150 E have been ueed for atudying fast preeesses involving pressuna np to 7.; laar sad also viscosity and density in men- wssk moleculrr complexes. A technique for obtsiaimg spectra in tioned temperature Interval have been investigated to clear up tbe range 90-150 K in liquified gaaem (like fraons, Ar or E» the character of molecular movosent In viscous liquids. Compari- hss been developed, fiy means of full lime shape saalyala the son of spin-lattice relaxation time and salf-dlffnsion coeffi- lifetimes of a number of hydrogen banded (In particular, the cient with viscosity shows that Stoxea-flnsteln relation is not complexes of earboxyllc acids) and charge transfer oomplexes fulfilled in temperature interval investigated and" fAf is not have been determined. At ISO K, these values depending em tha proportional Xof/p . Separation of lntrs - and inteiaolecular bond strength are varied from IO"6 te I0*1 s. The aotivatien contributions to 1} indicates that lntrsmolocular contribution ' energy of the dissociation process is dose ta the energy ef a is only 6* st low temperatures and doesn't exceed 20% at blgii breaking bond (£-12 kcal/mole), the frequency facter being ones. Summing vf tbe mentioned above one may conclude that for anomalsusly high (IOI6-I0Ia s"1). this proves the bend in s viscous liquids, jy?/JW#y ,r , dominating relaxation mechanism / trsneltlsnal state to he rather loosened. It has baem shews, Is translatlonal movement of molecules. This allows to use Tor- that molecular exchange process like AH...B1* B"»AH...B"t B', rey theory to lnterprete tbe results obtained. or AB'...B + Afl"—1H"...B + AH1 are going am with the total Kinetic parameters of liquids t correlation tias Z" ,mean c breaking of one hydrogen bend followed by the formation of time between jnaps Tj , mesn-sguare displacement <&'s> , and another, any blmolecular mechanism proving nnprefitabls. maximum approach of rescuing nuclei are calculated using experl- •ental data obtained. Analysis of these values in low tes.peratu.-i The method of determining the shspe of tba pretam potential » region and under high hydrostatic compressions shows that mo- function in a nydregem bond la suggeated, bassd oa the spin- vement of short molecules is carried out as a single whole on spin coupling of thw proton, which cam often be observed belew distances commensurable with molecule sixes. Substances consist- 130 E. In the csss of the only central minimum, this value is ing of large maber of 'monomerie links shift on distances com - markedly decreased. Thus, in ths pCO0...B...0CH0)~ lea the mensurable with sites of monoaarlc link. Movement of Urge mole- proton coupling value la, lees than I ops. while that In HC008 cules is seamed to carry out by successive movement of separata molecule being equal to II.S cos. The frequencies er proton klnstlo links. lbs classic case of large diffusion jumps is rea>- migration inside some complexes ef double-well potential llxsd in the. region of high temperatures and low pressures for function have been measured. It has been shown that these. all lionids Investigated. valusa grow with the hydrogen bead energy Increase, as ths potential barrlsr deoreaaea. The frequency ef prorea migratlem la strong OH...I<*»0~...HI* complexes is higher than I05 s"1 at 100 K. D3309 D3310 IXS RSIAIITIOB STUDY OF SUCEOSTHtK3TOHE 0? SLECTROLTTE COUNTERION N«R IN SOME POLYELECTHOfcYTE SYSTEMS S0LUTI0H3 H. GUSTAVSSON and B. LINDHAH, Department of Physical Chemistry 2, Chemical Center, University of Lund, 7.I.CHI2HIK, V.I.lCIKHAItOV. T.T.EHHOLAETA. Inatitutt of PhyaiCB S-220 07 Lund 7, Sweden Leningrad State University, £enlngr«d 198904. DS3B f NHR ijuadrupole relaxation rates and chemical shifts of several simple lens {Z3Na+, 37C1~, 133Cs+ etc.) were used to study counterion-polyion interactions for both synthetic and biologi- The effects of electrolytes on the structure of water and cal macromolecules. Important features usually found in the organic BOlvtmto have been widely studied by HUH technique. Na+ NHR studies of polyelectrolyte syntems are: inequality of This communication preeents the results of an investigation of T, and T,* relaxation given by the sum of two exponential decays, diaaagnetic salt oolutiona. Proton* deuteron and Bodius spin- and J non-lorentzian resonance signal. The utilisation of these lattice relaxation tines hare been measured as functions of tem- feature? to deduce the correlation time of the polymer-bound perature (tro» -5O°C to +120°C) over the complete concentration caunterioi. is described as well as the estimation of the quadru- range (including the saturated solutions on the surface of ••- pole coupling constant. An illustration of the principles develo- luble oryotala). B&t* vere also taken for partially and comple- ped is given by the system Na -poly (nethncrylic acid) .'The ana- tely deuterated solvents* All mo amir en onto were done with a lysis gives a description in terms of che correlation times,

pulsed spectrometer operating at 8, 16 and 20 UHB. quadrupole coupling constants and degree of counterion binding. The correlation time is found to increase strongly with Jecreasing The experimental renulto enabled calculation of ion solva- degree of ionization and this is attributed to a conformational I . tion numbero, acti>r-t*m energy of the thermal motion in the so- transition. The results are compared with those of the systenr lution end reorlentation times of the solvent moleculee* The va- Na+-poly(acrylic acid) and marked differences are found between lues obtained from the resonances of different nuclei are in the two polyanions. A similar analysis as fcr poly (methacrylic Bgrefflieat, It should be noted that prosent theories do not al- acid) is presented for Na+ binding to some mucopolysaccharide ways give an adequate description of the nuclear magnetia rela- systems. xation la the ionic solutions*

~~D3311 D3312~~

WADRUPOLAR H&AZATIOH KECHJUTISH OF IOHIC KUCIII 7Id HUCLKAH mAGJBTIC HB30NASCE STUDY OF MOLECULAR IHTERACTIOHS AND 23Ha IB BASIC SOLVKSIS II AQDEOOS S0LTOI083 0? POLffiTHYLBNE CLTCOLS i.I.POEKOVYHIS ana.Tu.U.KBSSEER, Moscow T.D.ZUCHEIXO, T.T.MAHK, and 7.A.M0I3EIE7, Inatituta for Institute of Chemical Sigineering. Moscow, USSR Problems of Cryobiology and CryoBadloine,tncr63R Aosdeny of The aim of this work is to examine, which of particular Soieiuea, Kharkov 310093. USSR; Inatituta of Colloid Chemistry motional processes in ionic solvation shell determines the re- and fete? CnaBlatry UkrSSB Aoadaoy of Solences, Kiev 252142, laxation rate of nuclei '14. and TTa in basic solvents. We have nssR"< measured tea spin-lattice relaxation times, Tlt in dilute solu- iqoeous solutlona of polyethylene glyools (tBB) era of tions of sodium and lithium salts in mixtures B+L, where B is interest due to their application as eryoprotootanta. HHR B a basic solvent (hexemethylphosphotriamide, dimethylsulphoxida, speotral oharaotariBtioa of aqueous aolutiona of ethylene dimetnylformamide, foxmamide) and I> io an "inert" solvent Caee- glycol and polyathylena gljool with molecular weights from tonitrile, nitromethane, CHCIj, CH^CI^). T1 were foend not to 100 to 3000 have bean atudlei aa'funstions of temperature and depend on T.'concentration up to as much as 0,7 mole fraction of oonoentration. It has bean found that each terminal OH-group L in the mixture of B+L. At the same time, the average mobility will gat one water molecule and auh atom of ether oxygen will of molecules increased considerably as indicated by viscosity gat two water molooulee when strong assotlations of PEG and and TL of deutaron data la B (deuteratad) + L mixturaa. Thua wa water are formed. A rapid proton exchange which ia aooaleratad arrive at the conclusion that the quadrupolar relaxation rates In aUnUm madlum and decelerated ia asid radium has bean cannot bo adequately described by the widely used formulae detected between PEQ terminal hydroxyla and water, fwo-atap yr^A-t; , where T£ is the correlation time of rotational or diagram of proton exchange with alkaline diaeooiation is translational diffusion of solvent molacules or the solvation proposed on the beae of UR apsotral analysiB. Hysteresis complex as a whole. Using Ifarshall-wannarstrom's theory, which phenomena of changes ia HB speotral paramtars duo to accounts for both the chemical exchange in the vicinity of an peoularltlaa of ioe formation in the system wera observed ion and the diffusional motions we found that the former, as on freeslng mad subsequent thawing of the solution. In this it regards to the firat ionic solvation shell, determines the cue large associates whioh dissoeiat* slowly after thawing relaxation rates of 'Li and. ^ffa ia basic aolventB and that this of the mixture are formed in the solution. Ihe raaulta exchange has tin dissociative mechanism. living times of solva- obtained suggest one of the possible meohaniamB of oryoprotaot- tion complexes with a reduced by one (as compared with tetrahed- ion aotion of PSO. Sy this neehanism obangaa in ioa atruoture rically or octahedrically symmetrical anas) coordination number 4 and dehydration of protein mnaromoleouloa ooour on freeaing ware estimated. Tor [Li(aiflO)j] 'complex we obtais this value to in presence of PBO. ' be about 10 sec. Spin-lattice relaxation times of ^li and 2%m war* mlao measured In the system watar-aeatonitrile. Ihe relative contribution of the chemical exchange to yi, of 7LTl"aad la* in their aqueous complexes is estimated and discussed.

1. a,G.marihall. J.Cham.Phya, J2., 2527 (1970) X 2. H.wannermtrom. Moiec.Phjs. 24, 69 (1972) D3313 D33W ELSOTSON IBLKCULAH MSBOHANCE IN LIQUIDS MOLECULAR MOTION, VISCOSITY AND THE STRUCTURE OF SOLUTIONS OF Y.Je.K>OORBtiOV and S.I.SALI70H. Kiev State University, NONELECTROLYTES O.F.BEIRtncOV, Leningrad State University, Leningrad, 199164, DSSR 252017, Kl«v, DSSH critical analysis of the original and literature data on Molecular ordering in several liquids leads to the creati- correlation tinea of rotational and translations! notion and self- on of the density standard waves of the vslant electrons /1,2/. diffualon coefficient* obtained by the NHR methods in water solu- A scattering of the laser photons on the electrons is possible. tions of nonelectrolytea of different classes is presented. As a result a paeudo - Raman (electron) (PR) broad bands This analysis-reveals some important observations connected are observed. Study of the properties or sucn. second light in with the existence of well-known minima on the curves o£ concen- liquid CeHe , CeHsCF3 , CHBii and CHHs tration dependence of these parameters and their relation to the is the aim of our research, the PH spectra in CLHG are shown in mavimji of macroscopic shear viscosity and to the structure of so- The excited light sources lution in the middle range of concentrations. The dependence of were a He-tie and Hc-Cd the stoichiometry of the extrema, their relative size and some lasers wi*-h light power abo- lh other parameters on the chemical composition, structure and shape Hr-CJ ut 30 ml. It's established I"-. of the molecules of nonelectrolytes, temperature, and the addition that the liriewidth of the of electrolytes, was examined. Taking into account some addition- pseudo-Raman bands and their al considerations from thermodynamics, light scattering and other integral intensity increase data, one can suggest that the presence of extrema is the conse- with the increasing of the quence of hydrophobic interactions in vater-solute associates. excitation frequency. The re- "7, suits of band parameters me- am? asurement are listed in Tab- le. The relaxation time of the electron density vibrations changes from 10"W aac (.Xnft = 6328 A*) to 4x10~15 sec (.Xetc =4416 A"). Change of the linewidth and intensity of the pseudov-Rsman bands • sais that this phenomenon The Object • sent interest energy CtHc 1500 ! 2100 900 transition is proximate

CeHsCF3\ 1500 2400 1000 to the frequencies of the • excited light. The paeudo-RBBan bands wasn't discovered in the replaced of methane. This fact points the absence of the electron molecular resonance. These liquids have disordered structure. 1. Biscar J.P., Kollias F., Phys. Lett., A4£, H 1, 191-192, 1973 a. Kollies N., Biscar J.P., Chem. Jbys. Lett., 26, 11 1, 82-W, 1974

D3315 D3316 TEE SPIN-LATTICE RELAXATION 0? THE PHOTOS' TAKING PART HIE HELAXATIOH OP THE ALKALI 1ETAIS I0IIS IIUCISI IN WATER SOLUTIOHS AKD KOLECULAH B11IAUICS OP THE IOMS IN THE BTDROGHI BOND FORMATION MEASES! EBVUtOElEBT . V.3.EOTS and V.D.HHH0DS1K0, Okr.Acad. of Sol. L.V.PUarev- R.K.MAZITOV. lI.S.Kumolcov Institute of General & Inorga- akj Institute of Phyaical Chemistry, Kiev, 252028, USSR nic Cheaiistry, Academy of Sciences of the USSR. Moscow 117071 USSR Concentratian and tenperature dependences of the spin-lattice relaxation tiae (Ti) of hydroxrl and ring protons in tte The process of relaxation of the alkali metala ions nuclei 7Id, 23Ha, 87Rb, 133Cs in water solutions is investigated. system a.e-di-tert-butyl-t-metylphenol-acetau-tetrachlorometan The relaxation rate dependencies on temperature, concentration bare been studied. On growth the aaetan cancentration in the of various particles in solutions, isotopic concentration of system under investigation the spin-lattice relaxation tine of the solvent, and for 133Cs nuclei the relaxation rote vs the outer magnetic field strength are studied. Basing on theac stu- phenol •eta-protons has established to increase and that of dies parameters of molecular dynamics of the particles that are hydroxyl proton pa£= tirtufch the maxlrai which has a shift; neareat to ions are dwtermined. It i£ shown that the rotary mo- to the range of bigger aceton concentratlona on increasing the bility of the water molecules near the alkali aetals ions can be higher, as well as lower than that of the water noleculeo in temperature. The observed effect is shorn to be depend on the pure water. The values of barriers Bt, that hinder the motion change of hydxoxyl proton anhilitv doe to the hydrogen bond of water molecules near some ions are listed in the Table. New fomtion between phenol and aceton molecules. method of relaxation rate meaaurament is proposed. This method is based on the integration of series of nuclear induction or It was established that the correlation tine of phenol gyd- spin echo signals during the process of relaxation. roxyl proton tied in H-complex state was growing by two orders in comparison with free lr/droxjl. The same effect is observed Table.

for phenol hjdroxyl protons tied by tne intramolecular hydro- Relaxing Concen- Sol- Temperature gen bond. Tha tfceraodjrnamios paranethers of the coaplex forma- nuclei Salt tration vent Ei range tion indicated from the spin-lattice relaxation tiae data was mole/1 kcal/mole °C

found to have a good agreement with the results from chemical i shifts measuring. 'li LiOl 0.326 H20 3.8±0.1 15-65 Nad 0.2:0.4 3.5±0.1 40 As it was shown, the spin-lattice relaxation tiae magnitu- "Kb RbCl t.O Ha0 2.9*0.1 5-65 de ft] mar serve as one of the scanty tests indicating the intramolecular hydrogen bond formation In the system. D3317 D3318 STOUT W MOLECULAR MOTION IS iKJOIW BY BB IflllECPLK BFECT IB A IB¥ AIIBOACn 10 THX HlGNaTIC BKUXiXIOI 01 SPIBS II LIQUIDS MB SHH-LATTICS RXLAIAIIOH.. v.A.DABAGAl*. T.H.KAZiSOYICH, Institute of chemical nyslcs o£ the Xaian State ledagogical Inatltute,Kaian 420021 , OSSB Academy ot Sciancea of USSfi, 117977• GBP-1, MOSCOW, SS8B. The fondaaental K.B.Bogolubor's idea about the Mexazehjr

&•; Tha atudy of aa individual line relaxation in nlltiplet 'C of relaxation times have been utillied in order to develope MB. spectra started earlier /1-4/, ia continued now. Belaxation a naw approach in the theory of magnetic relaxation of spins was measured la some '"c enriched and nonenriched liquids. On tha in liquida.The new microscopic theory have been constructed basis ot the theory developed earlier /2,5,6/ it is shown that the for the intexmoleculax dipole-dlpole meohanlaa of aUB-relaxa-

cross-correlation tine Tcl cj for the vectors CH^ and CHj can tlon.The correlation and MB-relaxstlom times has baen calcu- ba obtained fna tha difference in the relaxation curve initial lated by meanB of the interpartiole potential,the radial dl- slopes for the Inner and outer spectral lines. Aa found experiment srtibution function and the spin perturbutlon.lt is shown tally and theoretically, the polinomial approximation of tha rela- that the spin relaxation ia obliged to the molecular proces- xation curves gives initial slopes with sufficient accuracy. Bym- ses on the space correlation length which la much enaller in •atrj considerations suggest that there ere 6 independent auto- comparison with thB particle dlmension.The considered theory and cross-correlation tines for rigid aayametric molecules in lso- conforms with the experiment better that than previons' theory. tropic liquid. The aeveral inequalities follow from the aecond low It is shown that the well known Hnlibaxd's theory in which it le of thormodynamica* Then the fi^"1 number of definable autocorre- taken into account the molecular rotation at the noncentral lation times is less than that of independent correlation tinea, localization of the relax&ting npins is wrona; .The remar- the croaa-correlation tins give new information about molecular kable influence of the molecular rotationa on the intemole— reorientatianal motion. Oils approach was applied to nethanol for culax contribution of the DMB-relaxation rates have been

which measurements of *£"c i ^ made possible complete description found to contradiot to Hubbard's results.The influence of the of rotation anlsotropy without any model assumption about tha na- hudrodynantlc asymptotic effects of molecular thezmal motion of ture of motion. particles in liquid on the HHR-relaxation rates is predicted. At first the microscopic interpretation of the unusual tempe- 1. DaraganV.A., Dokl. Akad. Sauk SBSH, 212, o57 (1973). rature dependence of the IHB-tuadrupole relaxation in tha Uquid 2. Dar&gan V.A., Ehazanovich T.H., Stepanjants A.U., netalB and the liquefi ed inert gases have been given.The molecu- Chem. Phys. Lett., 26, 89 (197*). lar explanation of B.H.Kosyrev with coworkers experiment an the j. Daragan V.A., Ookl. Akad. Hauk SSSB, 232, 114 (1977). temperature dependence of ESB-relaxation In paraaegnetle solu- «. Deragan V.A., Knasanovlch T.N., Zh. Strukt. Khim., 19, 49 (1978). tions have been developed. 5. Warbelow L.G., Grant D.H., J. Chem. Hiys., 63, 544 (1975). 6. Bain A.D., lynden-Bell B.H., Uol. »ys., 30, 325 (1975).

~~i .~~

D3319 KUCIZAR MAGHBTIC RBSOSAKCE STUD! OF KIBCTHOETTE SOLUTIONS JS HUTCHES 0? TEX HEAVT. flXKB (D,0) WITH OHOAHIG SOLVENTS Id WIDE BAKE OT COTCBOTHATIOgS ADD TBDERATDBSS T.T.KUSCHBHKD, K.P.HISCHBIllOt Ii.T.IilXVlDOVA, Laningrad Technolo— gical institute of Pulp and Paper Industrj,I«nisgrad 198092 ,USSB Electrolyte solutions in water and in water-organic solvents at present have wide applications In different branches ot che- •ieai industry. But up to now there is no common theory allowing: to calculate all the properties of solutions. Therefore the application of BaB method is positively effective in the investigations of the structure sad properties ot the mnltlcomponent ays- teas, which are systematically studied in our laboratory. In the pitaent paper the proton spin-lattice relaxation rates have bean measured by the impulsive method in the following systemai aceton-SgO-Ial, hydrazlns-D^O-Bal, hydraiina-BjO-Bal, dlmathylsylTozlde (SDSOj-OjO-elactralyte (Sal, KI, Hbl, Csl), sulf olan-D2O-«loctrolyte. The proton-denterium laotope aT^hanga in the systems acetone— D20, DHSO-DjO, aulfolan-SgO is absent, therefore the measured rate of the proton rttlaxation depends only on the rate of proton relaxation of the orgiiilc solvent. In the ease of hydraslna-DgO system the isotope exchange takes place and the observed proton relaxation rate additively is summed up from the proton relaxation rate of the water and hydrasine. The received dependences of the relaxation rates from the concentration of the components confirm our earlier conclusion made on the basis ot the vapour pressure measurements, that in the system hydrasina-water-electrolyte the preferential coordination ot the hydrasine around tha ions of electrolyte takes place. It was established, that in tha mixed solvents D11SO-D2O and sulfolso-DjO,containing IQaol.JI ot the organic component, the proton spin-lattice relaxation rate at 25* C does not change with the addition of the alkall-ha- lide salts (Sal, KI, Bbl, Csl). Tha dependence'of the relaxation rate on the electrolyte concentration becomes apparent only at 70*C for tha DICO-DJO-H and at 100*0 for SBSO-DjO-Bbl (Cfll) end sulfolaATDgO-*^ systems. These phenomena may be explained by tne presenca ot the preferential coordination of the water around the eleetrolytlcal ions. D3401 D3402 NUCLEAR SPIN LATTICE RELAXATION TIME IN CRYSTALLINE AND PftQTOH AMD DBUTEfKW LINE SHAPE STUDY OF NEMXTIC PARA-AIOXY- { NEMATIC DB-PBB AND DCl-PBB AHISOLE. R. Y. Dong. E. Tomchuk. J. Lewis and E. Bock. I.P6CSIK, K.TOMPA, Central Research Institute for Physics, Department of Physics, University of Winnipeg and Department H-1525 Budapest, P.O.B. 49., Hungary

of Chemistry. University of Manitoba. Winnipeg, Manitoba. Proton spin-lattice relaxation time (T;) were measured at Canada R3T 2N2 and Chas. G. Hade Department of Chemistry. 90 MHz using 1T— *£ — ^/2> pulse sequence on di-butyl-phenyl- University of Texas, Austin, Texas, 78712 U.S.A. benzoyloxy benzoate (DB-PBB) and di-chloro-phenyl-benzoyloxy ben zoate (DCl-PBB) . The aim of our work is the determination of An na\r investigation of the temperature dependence of the end-group motional effects on to nuclear relaxation. In crystal- proton and deuteron line shapes of perdeuterated and par- line phase, DB-PBB exhibits a V shaped relaxation curve with a minimum at T = 170 K and Tlmln <= 250 msec, and DCl-PBB gives >nano- tially deuterated nematic para-azoxyanisale was carried out. tonically increasing relaxation'Lime with decreasing temperature

The spectra were obtained on a Brukcr SXP spectrometer and T- is approximately 150 sec at the same temperature. The T1 equipped with a fast Fourier transform accessory. The proton relaxation time of DB-PBB protons is shorter than that of DCl-PBB in nematic phase too, the ratio of those is about 2. We interpret and deuteron spectra were measured at 90 MHz and 13.B MHz our re«ults on the basis of existing theories. respectively. The temperature range extended from - IQQ'C

~~to - 135'C. The experimenal results suggest that the four~~

~~deuterons on each benzene ring are not equivalent, that the~~

~~asymmetry parameter, 6, (1) which measures the difference in~~

~~the tendency of the two transverse molecular axes to align~~

~~along the mean nematic director, is not zero, and that the~~

~~two benzene rings are probably twisted with respect to each~~

~~other.~~

~~1. R. Alben, J. R. McColl, and C. 5. Shih, Solid State Comraun.~~

~~11, 1081 (1972).~~

D3103 D311W • IS IKVESTIGA1I0!! QV REORIEHTATION OP SlffiCTIC C PHASE MULTIHncLEAH lUSSEnC HsSONASCS IHVSSHGATION OS DEAKH, FLUORIDE BY MAGNETIC FIELD BASSE LIQUID CRYSTALS- Yu.HOLTCHABtOV. P.k.BORODIN, Physics Institute of Leningrad L.L.SHEHBAKOVA.Y.A.SHBHBAKOV.V.G.Knlopin Radium Institute of SOB, Stato University, Leningrad 198904, DSSH Leningrad 197022, USSH.

Pulsed proton nuclear magnetic resonance is suggested to use The formation of liquid crystalline meBophase is investiga- to study orientations! relaxation of directors in multidomain ted-in the avstem of uranyl fluoride-water-acetone by methods of nmectic C liquid crystal. multinuclear magnetic resonanee.The temperature dependence of The experiment is to observe the free induction decay fol- PHR-spectra (60 and 100 oHz) is established anil compared with lowing a sudden shift of probe axis from magnetic field direction. theoretical dat* /V.The degree of order (S) is determined to be Prom here time dependence of the HHR spectrum second moment is not greater then Ot*l.The dependence of the S-value on hydrogen determined. On the other hand this dependence is calculated on isotope composition in acetone was found and investigated by using the base of smectic C model, in which under magnetic field the isotope substituted solvents.The increase of deuteroacetone con- director can turn about a normal to the oaectic 'layer with an un- tent in this system shifted the liquid crystalline mesophase tem- changed tilt angle. A comparison of experimental data and model perature range.Xn thia respect the hydrogen isotopic costposition calculations allows to obtain orientational relaxation tine which of water ia leas pronouncedtbut it shows up in a change of °PkR 2 characterize the rate of director motion on precession cone. cheaical shift valt.es of uranyl fluoride. BHR allowed to determine The subject of investigation was liquid crystalline 4,4y- not only the orientation of acetone molecules,but also that of - bis - heptyloxyazoxybenzene (HOAB). Orientational relaxation water molecules;for oriented molecules of acetone and waterfthe for HOAB tn magnetic field 4,69 kC lasts a little bit less than a,uadrupol splitting ia obserTedfwhich depends on the ordering degreefi.e»on temperature and compoaition.ln aqueous acetone solu- a second, values of

~~LSherbakova L.L. ,3herbakov V.A.,Seuakov B.T.Zh.Str.Chem.CBuss.),~~

2.8abidoau S.f. J.Pbys.OhM.,71,e74V (1967). D34Q5 D3406 OR THE POSSIBLE DI3THIBOTIOT 0? HWQ S01BCHIAR AXES IS or soatus SPH-LATHO* NBUTIC PHASE IK 0HULB3TBHIC LlqUID OBTBIIIB I.pfcsa. Cntrgi Seeeareh Institute for Fhyeice H-1525 BuQi,i»at, POB 49. Hungary D.9.Balsa, A.I.OvcharenJto, A.B.Trofimov, «.P.ChwnnpkoT The long molecular axla of PAA molecule IB derined In an unuaual way aa the principal axis connected to the smallest Institute of fhyaios of tha Ukrainian insiflwy of SoleneeSi' value of the moment of inertia tensor. This definition ex - Kiev, 253650, USSR presses the idea that the description of molecular motion ia not eetiafactoiy on the basis of the Keier-Saupe /Ms/ potential The proton spin-lattice relaxation la investigated In soas alone, tat we think that an additional term connected with cholasterio liquid crystals (onolesteryl formlste, caproate,etea- the rotational motion of molecules is necessary. The aum of rata). the MS and the rotational torn gives such a distribution The relaxation la of nonaxponantial character in the isotro- function of molecular axes which doean't coincide with the pic liquid and obolesterie phase of tha investigated substances nematic direction. The poseible angular distribution function in Bore law-temperature phases nonaxponentiality vanishes. was estimated on the basis of our FT-.'&IR spectra of nematic Toe nonexponential decay of magnetisation is analysed on •vS .PAA, and the consequences of this molecular motionsl model assumtion of two noninteraction proton groups in a kolecule of are compared with other results from the literature. sample whose relaxation occurs with different rates. The temperature dependences of tha two relaxation tines (long and short) and the weight factors (the latter is determining the proton nunbor in each group} are obtained by tha computer fitting of the experimental data. The long relaxation time shows a strong temperature dependence whereas for the short relaxation time it ia weeksr.The activation barriers of motions causing the relaxation are determined. ' The data obtained make possible to ascribo tha long spin- lattice relaxation time with that of aliphatic aid* groups of molecule and the short tias with that of the rigid core. The reaulta on relaxation in tha cholssterio liquid erystsla are compared with those obtained earlier for HBBA In the iaotro- pie and neoatic phases.

D3qO7 D3408 Proton Spin Relaxation in the Liquid Crystal PAA MDLECTUB KonOKS AfflJ PHASE THtSGITIONS IK PHSHC H.WOLFEL and F.NOACK, phyaikalisches Institut der Dniversltat CXOSOGAHBOBAHES Stuttgart, D-7OOO Stuttgart Bo, Pfaffenwaldring 57, Germany A,L. Blumenfeld, E.I. 7edin, Institute of Elamentoorganic - Compounds, Moscow, ll?813t US8B. Extending previous studies of various research groups /1,2,3*4/ we She cage molecules of unsuhstituted p-dicarboclosoboranea, have measured the following properties of the proton spin relaxa- with the general formula of CjB^^g, are either regular poly- tion time T, of PAA: bedra (nz*,10) or polyhedra "stretched" along the distinguished - the Larmor frequency dependence in the range from wio Hz to C-C axis (n=3,8). It is well known that solids which consist of 80 MHZ; globular molecules do not melt directly! but undergo several - the temperature dependence in the nematic and isotropic state phase transitions not necessary of the structural nature. In from 4O °c below up to 40 °c above the clearing point iT s»135 °C; particular, high temperature phases of such Solids, usually cu- - the angular dependence, i.e. the dependence on the angle en be- bic, are characterised by high reorlentatlonal mobility of tha tween the magnetic field and the director between 0° and 90° j aolecules and by long-range dynamic*-', disorder ia the reorien- - the effect o£ isotopic substitution by comparing PAA with methyl > tations which is typical for liquids. Such phases are usually deuterated PAA-d6. ' referred to as the plastic solids, ay use of Bason and IH-epec- The measurements were performed with a pulsed HMft-spectrameter with jf v troscouy it was shown (1) that p-dioarboclosoboransa (n=3,4,8, improved field-cycling facilities. Using a superposition of avail- 10) nave either one (n=3,8) or two (n=*,10) plastic phases. In able models the extended experimental data (a small selection is the graBeat work wide-line BmB both on protons ano^S nuolel shown in the figure) allow to separate several contributions to

and lî Tj» and Tu relaxation data in 420-120 K temperature the relaxation time: range were used to investigate the carboranns with n=*i8 and 10. - in the nematic phase by selfdlffusion (SD) and orlentatlonal The qusutitatfve aodel for the molecular motions in plastic order fluctuations (OF) with OP dominating below and SD dominat- 1 phases was proposed and thermodynanicel parameters were deter- ing above m 1 HHz; mined. It was shown that the molecular re orientations are lso- - in the isotropic phase by SD, OF and rotational motions (only tropic is high temperature plastic phases of oarboranes with weak). Near TT up to iT + 5 °C the OP term predominates, above n=* and 10, sad anlaotTojiic tn all the others. The results ob- this temperature the main contribution comes from the SD term. tained are discussed ia terms of trenkel's model of molecular reoPientetian* In solids, developed by Denan and Brat (8). The, 1. w.HBlfel,F.Hoack,and H.stohrer data obtained ay Leffler at al. (}) for ortho-iaomer at Carbo- \ Z.Maturforseh. 30a,437(1975) rane with tt=10 (it baa a large dlpol soseat) are also discussed. 2. M.Vilfan,R.Bllnc,and J.H.Doane The sttemptwas aade to use spin dynamics data, namely, .the Solid State Commun. 11,1073 abort-time oscillations of the magnotiaation In spin-locking (1972) experiment, for the study of molecular mot ions. 3. J.Pirs.P.Okleja, and J.H.Doane Solid State Commun. 14,877 1. S. Bttcalov, L. leites. Proceedings of the Vth Conference on (1976) fisman speetroscopy, miburg, 1976, p. 55*. 4. Ch.G.Wade,B.M.Pung.E.Bock,J.J. 2. I. Barman, C. Brett Hoi. Cry at., 2, 301, (1967). 1 Vlslntalner^.Tonchuk.and R.t. 3. k. Leffler et al., 3. Chen, rays., 63., 3971, (1975). Dong; J.Chem.Phys. 64,4806 (1976) D3409 03410 HIGH RESOLUTION l3C NMR OF HEMATIC PHASES OF LIQUID CRYSTALS or ins AECMiTic FOIIUODE SOLUTICBS R.TEEXXR, I.HEINHAA and E.LIPPKAA, Institute of Cybernetics THB mm sraoia - of the Estonian Academy of Sciences, Tallinn 200001, USSR ; and A.V.GEIBiSOV , Institute of High Uolecular Rapid magic angle sample spinning with proton decoupling and Compounds of Academy of Sciences of the U5SR,Leningrad polarization transfer was used to study the C high resolution HHR spectra of an eutectic mixture of MBBA and EBBA in the 19^004, USSB- nematic phase. The high resolution C HHR spectra, registered at 10 MHz in a 9.4 kG field and a 1.0 kHz sample spinning rate, con- The orientational effect of magnetic field on nematic solu- sist of very narrow lines, which make it possible to study the tions of some polyamids Das been shown Unrein for the flist chemical shifts and relaxation parameters of all carbons with time using BUR spect-a of solvent. Solutions of polyparabeni- high selectivity, and also shows the presence of a very highly amid (FEU) In Dim and H2SO4 and polyparepnenylenterepbtbal- ordered state with snail distribution function values, created anide (PFUUL) in H^SO^ have been studied. The essential orien- under these conditions. The direction of molecular orientation in tation ofupolymer molecules is provtj by Bpectrum aniaotropy the polarizing field is determined by the direction of the rota- of solvent molecules connected Kith the polymer and gives evi- tion axis. Both the chemical shifts and the T, values are there- dence for the liquid crystalline state of the whole system. fore angle dependent, but do not depend upon the sample spinning Temperature-composition boundaries of liquid crystalline rate as long as the rotation is fast enough 'frot > 10 Hz) for state of these systems, obtained with HUB method is in good complete ordering. agreement with the prediction of Jlorj theory for the rigid The relaxation rates 1/T. are influenced by the order fluc- polymers .The orientational and reorientatiooal velocities of tuations and increase near the transition points of the nematic liquid crystalline domains are estimated. phase. It has been shown, tor EPhll-HjSO^ solution, that the displacement and the splitting of the solvent s'igial is due to anisotropy of diamagnetic shielding.The nature of the interaction of polymer chain with U^SO^ has been investigated. Using PUR and 1' C DUE spectra of polymer, almost complete protonation of oxigen atom with the increase of the order of C-9 bond has oeen shown in FSA-HÔ^ and PFhTA-HgSO^ Bystema. It has oeen concluded from the analysis of *'c HUH spectra of polymer in SÔ^ that in the liquid crystalline solution all molecules of polymer are connected with the acid moleculesf i.e. uniform distrihution of polymer and acid molecules takes place in liquid crystalline domain.

~~D3411 APPLICATION OP HIGH RESOLUTION NMR FOR THE STUDY OF ASSOCIATION PROCESSES IN THE PLASTIC CRYSTALS L.L.KIHTYS, V.Kapsukas State University, Vilnius, USSR~~

An intensive diffusive molecular motion in the plastic crystals makes the high resolution NMR applicable for their study. The possibilities of study of molecular association processes in hydrogen-bonded plastic crystals by NMR 1H are analysed. The temperature dependences of chemical shift <5J and line-width, as the basic source of information, are investigated for a wide number of typical plastic crystals such as: trimethylacetic acid (I), cyclohexanoi (ii), cyclohexane (III), adamantane (IV) and others. The stay of a narrow lines and the formation of the satellite of -COOH line at the transition point liquid-plastic crystal for I and other carboxylic acids as well as for two- component systems I-II, I-III, I-IV is found. The uneven decrease of a at the transition point plastic crystal-solid state for I and system I-II, and the divergence of 6 = f (T), which is found to be essentially dependent on concentration ratio of i and II, for both directions of the temperature change is determined. For the systems I-IH and I-IV a change of the temperature coefficient of dependency « » f (TJ at the transition point liquid-plastic crystal of I is observed. An analysis of the obtained data for the systems of plastic crystals in combination with the wide NMR data for the analogous systems in liquid state allows to conclude about the promissing perspectives of the application of high resolution NMH for the study of association processes in the plastic crystals.

~~I -J-~~

~~CSJ~~

~~CD 112~~

NKR IMAGING IN MEDICINE AND BIOLOGY APPLICATION OF 'fMIMft KITH HAGIC-ANGLE ROTATION (MAR-NHRJ E. B. AHOREW. P. Al BOTTOMLEY, U. S. H1KSHAU, G. M. HOLLAND. B.SCHNEIDER, p.DOSKOClLOVX and J.JAKES, Institute W. S. MOORE. C. SIHAROJ. Department of Physics, and of .Hacroroolecular Chemistry, Czechoslovak Academy B. S. yORTHIHGTOH, Department of Human Morphology, University of Sciences, 162 06 Prague 6, Czechoslovakia Nottingham. Mottlrtgham, England, An apparatus for *H MAR-NMR measurements is described) per- mitting both BL and HR measurement of solid and liquid samples High quality proton NHR images of potential medical and bio- over the temperature range -120" - +1SQ'C. The spinning speed of logical usefulness have been produced by the multiple sensitive fl KHz, attainable in various types of construction, can hardly be point method (1,2) of NMR Imaging (Zeugmatagraphy)• An instrum- exceeded because of material limitations. Therefore line-harrowing ent has been developed which operates at 30 KHz for protons and by ^-MAR-NMR is mostly observed in systems with lines partially has a specimen access of 3 cm diameter. A thin transverse sect- narrowed by motion restricted in space, with some residual, ef- ion of the specimen, a few mm thick, is defined and scanned in fectively rigid dipolar interactions. In such systems line shapes about two minutes. The images consist of 128 by 128 picture ele- in conventional spectra correspond to the convolution of a. basic ments and have a resolution of about 0*5 mm. Images will be line shape function S(i>-*>,J with an orientation-dependent dipolar shown of thin sections of a live human hand, wrist and forearm, broadening function G (*>,-«_) and of small animals (rabbit and rat), whicn demonstrate excellent

'.•-..', correspondence with the actual anatomical features. No notic- ,dcos9 eable attenuation of the radiofrequency radiation inside the O—"• L tissue was observed. Current extension of the system to full In the KAR-HHR experiment- the effect of the function G is elimin- body sizes will be discussed. Advantages of this method of medi- ated so that the limiting residual line shape corresponds to the cal imaging are its lack of hazard, its penetration of bony struct- function S. In view of experimental possibilities, theoretical ures and its possible discrimination of cancerous tissues through analysis shows that H-MAR-NMR spectra can be successfully applied relaxation differences. in studies of various magnetically anisotropic systems. Examples wil~ he given of MA3-NHR studies on objects where this anisotropy 1. Hinshaw, W, S., Phys. Lett,, 48ft, 87 (1974); J. Aypl. Phys., is due to inhomogeneity of magnetic susceptibilityiin multiphase £7, 3709 (1976). systems (ions exchange resins), or on systems exhibiting motional anisotropy -(poiypeptide liquid crystals; swollen polymer gels 2. Andrew, E. R.. Bottomley, P. A., Ilinshaw. H. S., Holland, with either chemical or physical crosslinks; solid amorphous G. N., Moore, W. S., Simaro}/ C, Phys. Med. Biol., 22, 971 polymersl. In all these cases, informations on rapid internal mo- (19771. tional modes can be obtained from MAR-NMH spectra. Determination of the shape function 5 from MAR-NMR spectra makes possible analysis of conventional 'H-NMH line shapes based on eq.(i), yielding the shape of the function G which is an important characteristics of systems with motion restricted in space. The possibilities of this procedure are demonstrated on the II-NHR line-shape analysis of swollen crosslinked polystyrenes and of amorphous polyethylene.

143 \m THE KUBX-HASEK: ITS NONEQuTLIBRItJK PHASE TRANSITION* AND HEW OPTICAL PHENOMENA DDE TO NUCLEAR tJUABHDFOLE SUPERKADIANT SELFORGANIZATIOH INTERACTION, HUB.AND "FEEDBACK" IB LIGHT-ORIEHTED ELECTRON-NUCLEAR STSTEH 0? A SEMICONDUCTOR F.B0E5IGER, E.BRUN and D.MEIER, Physik-Institut, UniversitSt V.G.FLEI5HER, V.A.NOVIKOV, B.P.ZAKHARSHENIA, A.F.Ioffe Physieo- Zurich, Switzerland Technical Institute, Academy of Sciences, Leningrad 194O21,US6R

In- the new interdisciplinary field of synergetics /I/, systems In the presence of optical orientation in semiconductors /I/ are considered in which ordered structures develop out of random nuclear polarization depends on toe average electron spin S, which in turn is a function, of the effective nuclear field % acting on states. Ruby placed inside the coil of an LC-circuit /2/ is such electron spins. This mtual dependence of electron and nuclear po- a system. There, in a static magnetic field, transverse nuclear lariiation (internal feedback) gives rise to a number of unusual spin order -appears spontaneously, if the Al spin system is ne- features of the spin systea that manifeat theaaelvBa in a weak gatively polarized beyond a critical threshold. Thus, due to transverse field H. Sose effects are explained by/optical cooling .radiowave amplification by stimulated emission of radiation (ra- of nuclear spin syate* /2/. Experiments on p- and; n-type AlGala ser), a coherent, superradiant state is formed. For this disorder- carried out by •assuring of the circular polarisation (p) of lu- order transition, with the transverse rotating magnetization as •anescence allowed *oat spin aystea has fixed steady states. Vari- the order parameter, we developed a theoretical model baaed on ous factors (BMR including) say oauae transitions between these sta'ndard Bloch equations and on the dynamic equations of a heat- states. In that caaa hysteresis phenoaena as well as Juaplixe reservoir model for the usual spin dynamics in ruby /3/. We dis- changes or slowly, undamped oscillations of o value have been cuss the obtained dynamic raser equations far different modes of observed /?/• HI theae effacta depend on cryotall orientation. operation (continuous, pulsed] from which the threshold of the Strong "feedback" leads to the onset of instabilities. High sensi- raser,.its critical behavior near threshold and its transient tivity of thep value to changes is H« allow BUR to be detected response after Q-switch tuning can be calculated. These equations fktfz ' opticaly in an unusual-for-so— are then generalized to the case Where the raser is driven by an lids range of low frequences f. She figure shows the plot of $ external resonant rf-field whicVi leads to hysteresis effects in 75 the raser output'. He then compare a variety of experimental radi- for the As nuclei against the ation patterns with theoretical predictions. In the discussion angle between axis [llO] and 1 at H = 57 0e. Values of $ are special emphasis will be placed on the close analogy between the thrice the usual resonance fre- raaer, as a system far from thermal equilibrium which chew* the. quences in the fields H"Coee phenomenon of cooperative sel{organization, and a system at ther- iT 0 JB SO 90 1MB ISO 'W yt° where eiare the angles between mal equilibrium which undergoes a first or second order phase ;I and all possible As-Al directions, tha HfR observad an caused transition. [by nuclear quadrupole interaction due to partial subsiitutiox. of Ga by Al atoas in the cubic lattice. 1* Haken H. Synergetics, Springer-Verlag 1977 2. BQsiger P. et al. Phy*.Rev.Lett. JJ§, 602 (1977) 1. Laspel.O. Rhys. Bev. Lett. 20, 491 (1968) 3. Bosiger P. et al. Proceeding* XlXth Congress Ampere, 2. SyskOBOT.H.I.snd Perel.V.I.ah.Ikap.TeorJiB. 68, 1514 (1975) . Heidelberg (1976) 9* Bovicov.V.A.and»laiaher,V.G.IhJksp.Teor.»ia.?»t 1026 (1978) SPIN DYNAMICS Or UU DIKMSIOMM. stoKIIC SYSTEMS.

~~».J. foulil~~

~~KaMKUnih OoMt Ubontorita dtr Rijkiuniv«riictic Uid«n( poitbui 9SW, 230O u UUn, DM IMtliirlnrii~~

Studias pf spin djuaics of R«iMnlwg linsvc ctuin «j*t«as ba«« b««o eoBCantcatcd until now on the low f i«14 region. Espaciall; tb« rol> of «pin Hi diffuiion tua fa^an captuaUad, Intataitlng pbaooaau occur hovavar alao in faith ficlda (11 * «c - ^). aa adghc for ioacanea fa* deductd froa calculation* ift th« high ttsp«iatuc« liadt. In order Co icudy [hat* djmuical properties in [he experimentally avail' able fieldi, one hat to chow chain syitnt with relatively mall exchange coniunt*. .Hethoda to itudy ipis dynamic• include neutron diffraction, ESR and (requencj dependant auscaptibility awafureMnct. Ht hive uted proton ipin- latcic* relaxation tiae aeaiutMtntc to itudy the S • J antifcrroaMgnetie Iul in itB linear chain tyite* in Cu SeO^ . 5H2° * iaonorphi. Also the S > | alternating linear antiEerroaagnet Cu(H02)2 • 21H.0 hat been investigated. Special attention has been paid to the law temperature region. Our proton relaxation aeasurtawnta provide tha potiibility to observe V? eeparately the apinfluctuatiou along the field and perpendicular to it. In both syatema theie coaponcnti arc found ta exhibit completely different dependence on fieldatiength aod temperature. Remits near the critical fields are .especially interesting.

I A 111 « pRoninSt IBB smcr or DIPOLAR caoss-nBuucvricH INVESTIGATION OF UYPER7INE STRUCTURE AND RELAXATION IN AROMATIC VIM, OapartMnt of -Physical chswlsitry, Dnlvetsity of Groningen/ . 16, Gionlngan 9747 AG. 1t» Htth«rl polarization is not only observable for the directly polarl- as the electronic spin relaxation. Therefore ONP can be a useful zable groups, but also for nuclei that are in dose proximity to these groups. alternative spectroscopic mc*-h"H especially in cases* of short Polarisation transfer occurs through dipolar cross-relaxation transitions. living and radiationless decaying triplet states. Nhich-are also the basis of the nuclear overhauser effect (NOB), similarly to this latter effect the sign of the transferred polarization denenda on the The spectroscoplc potential of ONP will be demonstrated with in- correlation cis* of molecular tuablinq. Far proteins its sign '1B opposite to vestigations of excited triplet state complexes in doped molecular that foand in aaall Molecules. In relatively small proteins such as BPTX crystals, mainly fluorene doped with acridine. In connection with ;tH • £500) polarization transfer occurs to nuclei in the first shell surroun- EPR-measurements /2/ the full tensors of the fine as well as hyper- ding the primary polarized group. For larger proteins the ratio of cross- fine structure of protons in the different constituents of the relaxation to spin-lattice relaxation rates beconea progressively larger and complex could be determined including the signs of the tensor ele- polarization stay be transferred to larger reaions in the protein by spin- ments. In addition, the importance of the electronic spin relaxa- diffusion. An extresat exanpl* of this has been found in the case of glucose tion will be mentioned. It turns out to be highly selbctive. oxidate W* - 1SQO00), where almost the entire molecule becomes polarise:! by Hence It acts not destroying ONP, rather enhancing it construet_vL— this spin-diffusion process. Th* effect of polarization transfer by craaa- reluatlon provides valuable information on the solution structure of proteins In addition it allows detailed studies of nuclear spin relaxation and the dynamics of then •acrooolecules. 1. Colpa,J.P. and Stehlik, D. Chem.Phys. 2j_, 273 (1977) Stehiik, D. and Colpa, J.P. Chem.Phys. 21_, 2B9 (1977) 1. R.Kaptcln. K.Dijkstxa and K.Hi col ay, Nature U97B) in press. 2. Furrer, R. and Stehlik, D. Coll.Ampere, Dublin (1977)

A 1(11) ODHR OF PHANES: MODELS FOR DINERS, EXCIKERS AND CT-COKPLEXES PHOSPHORESCENCE SITE SELECTION SPECTROSCOPV ON ORGANIC MOLE- CULES IN SHPOLSKII 1IATRICES. D. SCHWEITZER. W. GOLDACXER, K.H. HAUSSEB and H.A. STAAB, Max-Plancl -Institute, Departments of Molecular Physics and K.P. DIKSE, Hax-Planck-Institute, Department of Molecular Organic Chemistry, 6900 Heidelberg. Physics, 6900 Heidelberg. Suitable systems for studying transanulax interactions are C.J. Winscom, FU Berlin, Department of Molecular Physics, phones in which two planar aromatic molecules are kept together 1000 Berlin - 33. by nethylene bridge*. The figure shows an example. Phanes with Electronic spectra of organic molecules in condensed phases identical units are models for-diners and excimers /!/, while generally exhibit inhomogeneous linebroadening due to site di- those with different subunits can be regarded as models for ex- stribution. Successful attempts to limit inhomogeneous optical dplexes cr charge-transfer(CT)-comploxes /2/. For instance. broadening by selective narrow-band laser excitation have been reported by Fersonov and coworxers for fluorescence of organic 0CH3 molecules in arbitrary matrices /I/. No noticeable phosphorescence line^narrowing was found for such matrices, however, when

~~• CN,R2 " R3 populating the triplet state via a SQ -* Sj absorption /2/. ' CH.R2 = R4 In case of mixed single crystals and Shpolskii matrices we ob-~~

~~served site selection and spectral narrowing under Sc -• s1 ex-~~

~~Optical Detection of Magnetic Resonance~~

1. D. Schweitzer, J.P. Colpa, J. Whnke, K.H. Hausser, H. Baonel References and H.A, Staab.' Chen. phys. XI. 113 (1975). 1. R.I. Fersonov, E.L. Alshltz, L.A. Bytcvslfaya, B.H. Kharlorov. D. Schweitzer, K.H, Rausser, R.G.H. Klrrstettar and B.A. Staab. - Sov. Fhya. - JETP, 3B, 912 (1974). X. B.turf. 31a, 1169 (1976). 2. X. Cunningham, J.M. Morris, J. FUnf •chilling, D.F. Mil liars.' J.P. Colpa, K.H. Hausser and D. Schweitzer. Chea. Phys. 29, Chem. Phys. Lett. 32, 581 (1975). . 1S7 (1378). 2. O. Schweitzer, K.H. Hausser, V. Taglleber and H.A. Staab. • Chem. Phys. 14, 183 (1976). A122 taiMatxtvm or nuoaa BUM: w CMMIC MDLECTLXS nmiae u HIGH 8ES0L0TI0H HQR 14N IN THE SOLID OPTICAL PDHPXWi CTCLB FOLLOWS BY ITOCLEM aVADxOPOL nSOHMCE COMPLBXES V.GMCaiSBiaK. E.A8IS0V, T.EM.ICHEVA, Kaliningrad State and B. Boroek*t Inatltut for Moa- and Fest- University, Kaliningrad 236040, USSR kSrperphy«lk< Bulin, FRG r Toe two-frequency pulse HQR method with an active variable frequency band filter la developed in apectroscopy of nitrogen. It hat bean •noun by optical pooping or excitation of trlj>l«t The Method la of great value for^the interpretation of compli- states that It la poaaibla to tranafer alactzon apin polarlaa- cated spectra complexes urotropine with crystal-hydrates and tlon to nuclear apin polarlaatlon via tha aolld atata affect, acida. both in anorganic |i| and organic |2| cryatals. At low tupar- -~ The programa with tlne-aharlng in nuclear quadrupole reso- aturaa thia pslariiatlcn la maintained for several optical nance la conaldered'/V. The number of NQR H lines in some comr pooping cyclea and thua la alao tranafarrad to tha ainglet plexea waa 16, for each four' non-equivalent positions o£ nitrogen ground atate of organic noleculea. A. new experiment has'been two spectral llnea being observed. performed to deatroy thia nuclear polarlaatlon in th* around Tha tesiperature depends on NQR frequencies..For the complex 1,-; atata via nuclear quedrupol reaonanca n I • 3/2 nuclei* Theae C«Br2.10HjO-2C6H12H4 agreement with X-ray data was obtained. In reaonance tranaitiona reault in changaa of tha -phoaphoreacence tha camplexea three nitrogen atoms in every molecule of HHTA are intanalty of the excited triplet atate. Thla nethod lmprovea connected with a CadijO)2* octahedron, the fourth nitrogen atom the aanaitlvity of HOB by at laaat three ordara of magnitude. ' foxMa a hydrogen bond with the bridge water molecule. possible appllcationa to atndy dilated nuclear quadrupol systems Valuable data on the number of non-equivalent positions of will be discussed. reaonant atoms in crystal lattice obtained by tjo-Erequency method are of great interest for the theory of hydrogen bond In com- plexaa. In two ceoplexes low temperature phase transitions were observed.

1. Grecblshkln.V. and Shls&Kln.E. Sol. state. Physics 16, 1542 |1| Mollenauer, L.F.I Grant, W.B., and Jeffries, CO. (1S74). • Phys.Rev.Lett. 20, 488 (1968) |2| schuch, a. spring Heating of the German Phy*. Soc., XBln, Feb. (1975)

A125 IQS snroi or mrr"""-" CHYSIUS or aouo SOLDTIOIS •^.•"TT IJI.1LYJIOT, m»tttttt» of Or»«u>-»la«ant COBJO- uni AOSAOT at SolanoM ft th« OSSHt Ol.Tartlorm is, 117312 Moscow, 0»» Iha rtudy of 1QR iptotra of «olecnl«- orjital* of aolld BW. ttat *»••• ooour «««rt oW»«t« In tt»ir W» tttctn camsMTti to th. fttn at t*» oH«»»»4 eo«oiw>t.| their •ulUplloltj lo«nutt,«u xmtio* of tha lntaayal 1»- tanaltH* la th« Miltiplrt •paotr* ohame aoooroln* to their oonoentratlon, and tt» line mitM trm»*oj« TUfilMAf. »• mnbar of Una* and their retatlw iBtejral isttuWaa u* described bj • Wncadal. Ttare are no ajrta—Uo «lil«« of •qa fnoaoolw tn • tamm of ajratam if the laamrlty ooa- oantmtlon la eWwad while la wml ajata» • neOar fra- quenox aMft If raoorted mtb. tbs ohandmf lavnzltr ooaaauii* tlon. In the l»ttar oaa. • llnaar da»aBd«Bea »at«aam fwqueaoj change* and tha ererm«s oloaa paesbw oaafflolairt la obsarre*. The free tea Is tha linear dependence la a Talna olaaa ta tbs SQK freqaanar of tha f»a •olaeal. (l.a. to tta «aa data). The line widths ohaafsa an consletent with tha antropj ohaa- gaa of binarr solution!.

r A1301 A1302 QUADRUPOIAR INTERACTION CONSTANTS IH SOME JI3 THE UHK Of IHS HQ,B DATA FOB irra DTfHjHTOAL M0QE& ANALYSIS 07 DIUMAGHETIC GAHHETS XBK CBXSTAI, STBOBTDEE 01 1,1,1,3-TKSBAOHI/SfOmOFASE H.HOJCIK, ••SBIERAMOWSF.I. Institute of Physics Polish A.D1HILOV, TU.QACHBaOT, and I.iatSBT'IV. Perm stats flniversity. Academy of Sciences, 02-668 Karsiawa, Al.lotnikdv 32/46, Poland Pen 614005! TOSH

~~Quadrupolar splitting constants were investigated in poll- To investigate a structure of molecular crystals, in some~~

~~crystalline samples of Ca3LlMgV3012 and Na-jSCjVjOjj as well as in cues it is necessary to consider molecules as rigid bodies /V~~

monocrystalUne x3Ga5012. These materials are interesting for the while In other eases the Internal degrees of freedom are to be large number of resonating nuclei, uhich are situated in the posi- taken into account /2/» In this paper n~Q£ method has been appli- tions of various point symmetry.In policrystalline samples the NHR ed to the discussion of the quest-Ion concerning the* choice of signals were observed from the following nuclei: 51V in tetrahed- . . a tensor defining the Debye factor* HOB "ci has been observed ral sites, 45Sc and 7Li in "octahedral sites and J3Ha indodecahed- In 1,1,1,3-tetrsehloropropane (CCljCHjCHjOl) in the temperature ral sites. The observed spectra, exept for 7Li spectrum, reveal range from 77 to 170 E when the crystal II exists, the crystal the second order quadrupolar effect for the central transition II consists of trsns-confomera of the molecules CCljCH^CHjCl /in m -i .**- m • - i-/. Additlonaly, the first order effect was ob- /}/. The NqH 35O1 frequencies served in fcbnadium and scandium spectra. The measurements were at 77 K have been me soured . performed in magnetic field range 3-13 XGs. Besides, MR investi- earlier /«/• Toe experimental gations df 71Ga nuclei were .carried out in single crystal of data for the frequency pj v3Ga.o12 at 11 MHz. rhe satellitary lines were observed as well as g. hare been fitted by means of the shift of the central line. Spectra from policrystalline samp- "8 the leasteatiare method using if les were elaborated applying the graphical method presented In the formula III, whereas for single crystal the theoretical angular dependence was fitted to the experimental data. The quadrupolar. interac- The mean-square angular dis- tion constants eq Q/h were determined. All the'measurements were placements (KSAD) of SW ten- performed at liquid helium temperature. sor principal axis OZ fort=O The following values of quEdrupoIar interaction constants were hare been obtained from the equation " ' obtained: ' Wn ( ^)/ Samples Nucleus Site e-q Q/h It appears from the Hftf! data thats 1) HBAD of the C(J)01 tetrahedral 5.936 bond is greater than MSAB of the C(1)cl bond) 2) to discuss the si. tetrahedral 4.150 Debye factor in the structural investigations of 1,1,1t3-tetra- 45SC octahedral 7.500 chloropropane, it Is necessary to take Into account the inter- ^Na dodecahedral 1.052 nal toraional vibrations of the atom groups about the C(1)C(2) 71G tetrahedral 5.496 and C(2)C(3) single bonds. Y3Gas012 1.Cruldtsbenk,D.W.J. Acts cryst.9,754 (1956). H.Lonsdole.K. Acts cryst.14, 37 C1961). 3.Kol«aor,V.P. et el. J.Cheo.Thonno- 1. H.M. Krli, S.G.Bishop, P.J.Bray, J.Chem.Phys. 49,557 /196B/ dynamlcs 1974, 6, 613. 4. Semln.G.K. at el. Zh.Struct.Khim. 7, 117 (1966). 5.Bledenkeppt D. et si. fler.Buna.Phya-Cheo. 70, 788 (1966).

A1303 A1301 BFiBBITIE 01 TSX ISasB II A HUCLEAIt qHADRDPOlE RESONANCE STUDY OF OLICOMERS IH THE FESSO- T.r.»MKT«mrni. l-.annATSIP. XaUningni state lC PHASE OF nCl-DCl HOED CBTSIAIS. J.E. BROOmtAM. DepgrtKnt of Kallnlngral ZJ6040, usaa.- Phr.lc, Dnlveriit; of Florid*. Calnenllle, Florida, 32611, U.S.A. AC low teeperatucu. HC1 and DC1 crfitallixe in an orchorhombir. struc- OB* doable iqjMHR reaonsne* method bad. been (100104 In the ture! watch haa been •howi to be ferroelectric. In chla phaae the Boleculea laboratory trams for two systems of nuclear spinal protons sod fon zigtat hydroBra bonded chalna which Interact only weakly ultb each other. nitrogen nuolei. le bad considered that relaxation, times in sero Frevioue Hq> studlaa /1,2/ of 3SCl(I-3/2) have Indicated that the predominant field of the proton system 7J, sad ojiadrunolo system Tit an eolecular Motion In this pbaae la llbratlanal In character, superinpased by a longer than the time of the crossing cycle of levels f . te hare poiaible w--s«r 90° soleeular flip proceas that occura between the zigzag defined similarly / 2 / the signal to noise ratio with, which the chalna. The rate of theae 90° flipa appeara to increaae rapidly aa the ferro- */ViqP spectra can be'measured. electric phase tranaltlon la approached from low tesperatures. HC1-DC1 nixed It has bees proved, that the application .of two-frequency crystala offer the opportunity of a unique study of the detailed features of satiety of auadmpole system leads to the Increase of signals the 90° flip proceaa. Because of the chain-like structure of the ortharhombic intensity In doable aqp-HB resonance. Intensltr of the line 1^ phase, the sized ayaten can be considered ss a series of oligomeea of HC1 (mo- is small / Z / and this signal can not be obMrnd at all. Using nosers, dlaera. etc.) linked in a zigzag chain embedded in a lattice of Del or two-frequanay satiety on the certain frequency (-fyi for example) vlce-veraa. tola viewpoint is supported by infrared atudias /3/. However s 90° and OB froqasnay, within the sweep of tte possible frtcueneies' flip by an isolated HC1 Molecule could change It fron being a sunoser to a Bea- ' range, in tba moment of selsure of the 11ns % the Increase of. ber of a dixer or triser. etc. depending on the neighboring iaotonic distribu- f-".' the signal Intensity will he taking plaoe. tion. An DQK study of these "ielanda" of ollgonara gives a Cl Bpeccrus con- Thu*, this aatiiod.aUows us, to make the total, dmolntiax or sisting of a nuaber of broad BQ.R lines, with intensities that appear to be re- tne oomBUoated moltlalsx-SDeatra W& srlth tiae prasauu of seve- lated to the statlatlcal dlatribution of the ollgoeers. The spoccra were ob- ral uoaoBlralaot positions nuoleers nitrogen In arymtal's lattl- tained as Che FFT of the free induction decay, and a series of spacers were ob- M. Sw numerous inf ormattons about double sQMDS resonance / 1 / calned »a a function of tespttrature In Che orchorhoabic phaae. existing nowday In a numbmr of cans ar» In need of control by Reaeacch supported by the U.S. national Science Foundation. means of two-freouenoy method, sa lines 4 In many oasem bad 1. Okuaa, H. Hakaaura. N. and Chihara, H.J. Phja.Soc. Japan 24.4525(1968). bean not observed sod only asauminc definition far oonstsnts 2. 0'KeiUy, D.E.J Chea.Fhya. 52,2396 (1970). Q mi. *l bad. 3. Cussonl, M. and Zerbi, C.J. Cbea.Fhya. 60.4662 (1974).

1. Xbrada D., Physio. Reports, 290, 4 (1977). S. BUaa •., HmU M., Omredkar a., Prelisnlk A., Sellgtr t,, •opsaela I., Birenbers £., 3. ahem. H)ys., 57,12, 5087 0*972). A1305 A 4306 CONCENTRATION FLUCTUATIONS AND QUADRUPOLAR SPIN RELAXATION A HQR STUD! OF STRUCTURE IBS TAflTOHERISM CO HiLOGSN-SUBSTITUTBD nTiTnlimmmnremuR IN BINARY LIQUID In-ALLOJS A.H.Hesmeyanov, D.N.KravtBov, A.P.Zhuxov", L.S.Colovchanko E. Helhreter. H. v. Hartrott, J. Hoehne, D. Quitmann, J. RoSbaeh. Institute of Organo-Slsnnt Compounds of Academy of and P. Willeke, Xnatitut fdr Atom- und Festxorperphysik, Frele Sciences of USSR, Moscow, 117813, USSR Universitat Berlin, Boltzmannstr. 20, 1 Berlin 33, Fed.Rep.Germany 'Institute of CiyBtsllography of Academy of Sciences of USSR, Ibscow, 117333, USSR In binary alloys of In the quadrupolar spin relaxation RQ has been studied rather extensively by Beveral authors /I,2/. Here we try to demunstrate a close connection between local con- The influence of dynamica of tautomeric processes centration fluctuations and quadrupolar relaxation rates, using a (exchanges) upon Nqs spectra has been discussed. It has been generalization 121 of the quadrupolar relaxation theory of Warren shown that in th. case of a slow exchange Cu>q-'uc»1) and Sholl /3/: between mo tautomeric structures characterised by the NQR

~~frequencies CM, and~~

For the fast exchange = ui1+- i>2 au) should ba observed, where D is the diffusion constant. p? is the probability of the molecule being in state 2. The enhancement of R observed in many alloys can be de- The 3501, 81Br and 127J NQR speetra have been recorded Q scribed only by this expression if the V-,. S™ term dominates for polycrystallins hslogen-aubetituted diazoaminobensenes (V^ S can be neglected as a first approximation). This enhance- in the temperature range 77-3OO°E. The existence of the c NC ment correlates with strongly negative enthalpies of mixing. coapounds 2-ClC6B4IT}HC6E4I-4 (1= E, ?, Br. M02) in one Therefore we discuss 5 in the hydrodynamis limit (k-*O) in the tautomerlc form containing an intramolecular hydrogen Dond CC frame of confonnal solution theory using thermodynamic data. An H-H Cl has been established. .It has been found that in anticorrelation of 5CC(O) and RQ is found, in contrast with equ. crystal the compounds 4-ClCeR4ir}BCgH4X-4 (I = H, F, Br, HOg, (1). However taking into account the k-dependence of S , the CH,O) exiBt in two_ tautooerlc forms: cc correct dependence of the alloy enhancement on Scc(k) is obtained. 4-ClC6H4HHH=llC6B4r-4 and t-ClCgH^Hs HHHC6H4X-4 the ratio or which has been determined and shown to depend 1. CartUdge, G., Havill, R.L., Tltman, J.: J. Phys. F £, 639 substantially on the nature of the subatituent Z. (197Q;Heighway, J., Seymour, E.F.W.: J. Phys. F, J., 13B The specific features of tautomorism in the czyBtalB (197I)i claridge, E., Hoore, D., Seymour, E.F.W., Sholl, C.A.: " of 4,4f-dichloro- and 4-,4t-4iiododiazoaminobeEzenes have J. Phys. F, 2, 1162 (1972) been discussed in resorting to ths previously reported 2. Hartrott, H. v., KShne, J., Quitmann, D., RoBbach. J., Weih- literature X-ray data. reter, E., and Uilleke, F.: to be published 3. Warren, W.W., Jr.. Phys. Rev. Alo, 657 (1974); sholl, C.A., J. Phys. F, ±. 1556 (1974) i. Bhatia, A.B., and Thornton, D.E.: Phys. Rev. B2, 3004 (1970)

A1307 A1308 EPG THISOh AT THE V51 HUCLS.US IH SOLID VANADIUM ELECTRIC ERECTS IH SQK SPECTBOSCOPX C.K.smm. E.Y.BHYUKHOVA, Institute of Orgaao-Eleaent H.I.Iazukova and T.A.Gubanov, Institute of Chemis- Compounds Academy cf Sciences of the USSR, Ul.Vavilova 28, try, Ural Sciences Center, Sverdlovsk, USSR 117312 Moscow, USSR

The calculation of electronic structure of vanadium oxideB and • It baa been found thr.t the field constants of HQE frequen- vanadates of s,p,d and f elements have been carried out by the MO cies in molecular orystals are highly characteristic values LOAO method in the Mulliken-holfsbers-tielmholtz approximation with which enables to estimate the electron generalisation degree tne self-consistency on charges and configurations and discrete va- in coordination interactions and complex formation. 1 compari- riation X method. Using the results obtained, the characteristics son between the rednoed BQR frequencies- and field constants of quadrupole interaction (the electric field gradient(£FGj at thit tot homologous oompounds containing different halogen atoms 5 V ' nucleus, assynetry parameter, directions of main axes) has been makes it possible to estimate the magnitude of intramolooular calculated. ' fielus. The EPS at V51 in VJOJ and vanadates sppesred to consist of the The founa values of intramolecular electric field for a two contributions which have the sue order of magnitude snd, depen- series of halogen derivatives of group IT coincide with the ding on crystal structures, the opposite or the same signa: the lat- calculated Tsluse snd with other experimental estimations* tice contribution and the valence one. The latter contribution appears in the HO method only snd is stipulated by the covalency of chamicsl bonds and the overlap of the wave functions of different atoms. Be- sides nanBymmetrical distribution of 3d snd 4p electrons, the consi- dersbls contribution in E7G in vanadates is srissd from electrons of 3p shell. The electronic structures snd electric field gradient tensor havs been calculated for semiconducting snd metal phases of T0£ snd T2°3* Contrary to the vansdiumCV) compounds the EFG at T^1 nucleus in this oxides is due to 3d electron distributions only. In the metel phases

of YOgBnd Y2o3 because of snergy level quasidegeneration it is neceB- sary to take into account the spin-orbital and thermal Effects. The EFG values calculated by MU methods agree well with HUH data for ordinary nuclear quedrupols moment Qs-0.05b and an introduction of another Q magnitudes for interpretation of BUB experiments is not necessary snd ia connected with ionic model inadequacy. Thus, the application of cluster calculations for interpretation of quadropole effects in solids is more reliable than iomio and crystal field theories. A 4309 A 4310 23 Z 35C1 NQR STUDIES ON PENTiCHLOROPIIKNOL-AMINES HYDROGEN IB IIS D QUABhuTOLE UTERACTIOI II SIIGIiB BONDED AD0DCTS CRYSTAL 07 SODIUM filSELSSITB ; I.S.VHOuBADOVA iSD A.I.H031YAK0V, I.V.Klrenoky Institute E.GRECH? -T.TfiTJgwrr mid L.SL'BCZYK, Institute of ChsaUstry of Physics, Academy of Sciences, Siberian Branch, University of Wroclaw, 50-383 Wroclaw, Poland Krasnoyarsk 66003$, USSB * Institute of Fundamental Chemistry, Technical university 71-065 Szosaoin, Poland Is contrast to the mil-known alkaline trlhydrogeienlte fa-

mily M*H3(SaO3)2. tha biaslenites M*HS«O3.where M* 1B an alkali- A eerie* of hydrogt.ii bonded oonplaxas of pentaahlorophenol ne metal ware not studied almost. There are no data on their with various N baaea, covering « wida ranee of ApK,, values, structure and properties excepting wsH3e0~. Zta atructure has 35 was investigated using C1 NQR. been determined by X-ray diffraction [1] . According to [1] tbe sin- 35 lHo average frequencies of C1 N

~~1. Chou Kung-du Scientia Sinica v.XII,Uo12,1963.~~

A13U A 4312 ELB2TR0I-IUCKBAK QUABHOTOIK CODPLIHG, Al NUCLEAR MAGNETIC RESONANCE IN YTTRIUM ALOMINATE IBI»CED BT EXCBAHGE IBTEHACTIOH. HUC- T.GROCHULSKI, W.2BIERAH0WSKI. Institute of Physics Polish LEAR QUABEUPOLE RESOVAISE II C1DSTHW i [Academy of Sciences, 02-668 Warszawa, Al.Lotnikow 32/46, OF THAH3ITIOS METALS IOIS „. * ' \ Poland T.E.PADJZIL'EEaO, H.I.BELH3EII and A.V.AB- L07, Institute of Cheadstry, Academy of Sciences, Moldavian The NHR measurenents of hi in YAlO^ single crystals are 338, 277028 Kishinev, DSSS presented. The crystals were grown by Czochralski method and annealed in order to avoide strains. Yttrium aluminate has distored Tha specific •eebanism of electron-nuclear quadrupols coup- perovsfcite structure with four non-equivalent Al * sites. In or- ling, Induced by exchange interaction between peramagnetie lone, der to simplify the analysis the angular dependence was measured ia predicted. Effective Hamlltonian of quadrupole lnteraetion ob- in the planes perpendicular to the crystalographic axes a,b and c. tained by the. method of Invariants looks as follows 1 The measurements were carried out at 300°K and at resonance frequency 5 MHz and 10 MHz. Quadrupole coupling constant /eQg/h/ and the asymmetry parameter were determined and are equal to 1.30 KHz whare 1, j and •< number the aplna of ions and nuclei respective- and 0.2, respectively. The orientation of the principal axes of ly! iS2r' i the sat of components of the second rank spherical 8 the electric field gradient was also determined. Similar measure- tensor forming the representation of the point group of clus- ments were performed by K.A. Hflller et al. in LaAlO^ /!/ and the ter; 3ir,r",r') an the constants) PJJ" is unit antlsymmstrlcsl values e*Qq/h =.16 MEz and ff » 0 were obtained. One can easily tensor. EUctron-naalear qoadrupols coupling Induced by exchange notice that in YA10, both parameters have greater value. This lnteraetion leads to the possibility of the-qusdrupole resonance* fact indicates that in aluminates, similarly to orthoferrltes /2/, on nuclei of paramagnetic ions even if it is forbidden in the mo- the distortion from perovskite structure increases with decreasing nonuelear fragment of the cluster. The essential condition of the rear earth ionic radius. The nonzero value of £ in YAIO^ is in effect is orbital degeneracy of tha Hoitler-london statss corres- good accordance with EPR experiment /3/ which gives the nonzero ponding to the spin multiploto of the Halssnberg model. Ins IQE value of spin hamiltonian parameter E for Fe substituting Al calculation is carried out for trimarlc antiferromagoetic clus- ion. The values of eQq, f) and the directions of principal t«ra with spins of ions S -1/Z and nuclear spins I* -1-3/2. The t axes were calculated assuming the pointfultipole model. It was ground state of trigonal cluster Is tha qnadrnpols-aetivs orbital found that the contribution from quadrupole3 can be neglected doublet 2B. Inargy gap, between Kramers doublets Is A - /D2 *S2', and the best, fit to tht experimental data Mas obtained for the O and d being the parameters of antlsymmstrie exchange and of oxygen ion polar!zability equal to 0.7 8 . rhombic distortion respectively. Quadrupole strueture of Kramsrs doublets looks as follows 1

«T- ± A ±38(4, .L,,IJB/4A fZmf^ - I(I+1 )J (2) 1. K.A.HAller et.al. Phys.Letters 9, 223 /1964/ X single line of »QB is poaalble in tha absence of magnetic 2. M.Marezlo, J.P.Bemelka and P.D.Dernier Acta Cryst. B26, 2008 fisld. Zeeman atruotur* of IQB spectra under different orienta- /I970/ tions of external field has been Investigated. Static rhombic 41- 3. R.L.Phlte et.al. Phys.Rev. 136A. 231 /19G4/ -ns of trigonal ayatam reduce the quadmpole moment of the jter das to removing of the orbital degeneracy. A magnetic lisl'd parallel to tha plan* of tha duster also leads to tha reduction of tha quadropole interaction.

~~A , A 4314~~

OH APPLICATION OF NUCIB1E QUABBUPOLE RESONANCE. mo-iBEquraci HHTBOD of urreariGiiiai ar MTMI-LKTBL qtuimuvoia : TO IHVKETICATI0H3 OP PHASE TfiAHSIIIOIS SPBT BIHTHI . - i.KHI, g.UHBIWlBI. Para State University, Farm 614005, DB3B D.P.BalBa. A.V.Bondar, A*Ja,Gordon, S«VaHaltsev. Institute of Physics of tha Ukrainian Academy of Sciences, Kiev, The two-frequency r.f. pulse action on tha multi-level £52650. UBSB. quadrupole spin system make a it poaaibla to study the spin The theory of the electric field effect in the nuclear quad- syatam response by means ol tbe two-frequency spin-echo signal rupole resonance (tfJEO in developed for toe case of the structu- detection, and may be used as a method of investigation ot ral phue transitions (FS). The temperature dependence of this relaxation proceaaeB in the spin system* with unaquldistaat effect ia firat discovered in the vicinity of the Fr in AgjSbSj. spectre. It ia quantitatively described by this theory using the data on Uaing tha two-frequency pulsed B(JB apeotrometar construct- the teaperature dependence of the dielectric permittivity close ed by anthora allowing to operate with one-, two- and nUti- to the PI temperature in Ag^SbS^. It is concluded that PJJ in -pulaa ssqueneles, various aulti-pulaa r.f. action programs question should be a ferroelectric one. hare been examined for soae qnadrupole spin systems In samples 2he equation for the nuclear quaorupole relaxation transiti- containing nuclei with spin I > '/2. She following polycrystal- llne compounds are studledt SbCl. (resonance of nuclei 8b on probability is obtained for the cases of the first- and second- 123 209 185 187 order PI in the long-wavelength approximation. It be cones the and Sb), BIClj ( Bi), XBeau C Be and Sa) ate. in known equation for the Becond-order PI containing the critical teaperature region 77-300 I. Optimal conditions for observation increase of the relaxation rate £J1 near the PI temperature, Sar of Ttrioua two-frequency quadropala spin-echo algnala hnre been the f trst-order PS, far fro« the critical point, this increase is found* Some of new features of relaxation procaaaaa in multl- absent, as ia observed in a number materials, including AgzAsS^, -leral qnadrupola spin ayateaa hare been mealed. and here is ascribed to the betesophase fluctuations. Transforma- tion of f irat-order to the second-order ±"P in Ag^AsS^ under the high hydrostatic pressure results in an usual increase of Tu near the PC teaperature in this experiment indicating a suppression of heteropbase and development of critical fluctuations*

~~A1315 A 4316 19? mm AND 35oi SQH STUDIES OF HOXECULAB FRAGHEHT OS THE CALCULATICK METHOD OP THE ELECTH01I DEBSITIES OF THE ELillEIITS 0? V-TH GROUP m~~

19 "The teaperature dependence of F (NICR) and^Cl (BQB) The formulas connecting the bond orbital electron densities spectra and spin-lattice relaxation in crystal compounds of the of the elements of 7-th group with the NQS specral parameters CljPdTCCCTj^Clj^ type (n=1, 2, 3) has been in7estlgated.the ( or frequencies ) in molecular crystals are discussed. The elec- data obtained manifest a number of dynamic peculiarities in the tric field gradient tensors produced by the each bond orbital are crystals. transformed to an axis system oriented in some way to the bond The reorientatloas of PClj and CTj symmetric atomic groups orbitals. Diafnna!L2.z&tion of the total tenzor gives the orienta- were obserVed, tbe first taking place In all the three com- tion of tte principle axeB and the diogonalized components deter- pounds and the second occuring.ln two of them (with na2fl3)« In mining t!ie Hqp frequencies. Aa an example the application of the tha compound with n=3 the whole fragaent CCCFj), is found to total e'-cpresaians connecting the HQH spectral parameters with the reorientate, too. aoraovar, in these crystals there is tht. ao- bond orbital populations and s-characters is presented for differ tlon of aayamatrlB atomic groups CCO»j)012 CD and C(Cf j)^Cl rent coordinations and hybridizations of tbe resonant atom. In C2I) between three positions with varioua potential energy- the case of the nuclear spin I = 3/2, when these parameters can- minima, one being lower than another, fhis conclusion is aada not be determined separately the analogous expression is derived on tha basin of tha following facts, (i) In tha groups CD for the NQJ2 frequency. and (IDf at the increase of the temperature, the spin-lattice relaxation time 9,. for the ^'Cl nuclei decreases exponentially and tbe }5C1 IQB signals fads out essentially below tha sample melting point, (li) Anomalous long times 1^ are observed for tbe 19T nuclei in these fragments, (iii) the fluorine absorption line second aoaent either conserves the rigid lattice value up to the aeltlng point (fragaent I) or changes (fragaent II) in such a manner that it remains higher than the value calculated for the simultaneous notions of the C*. group and the whole fragaent H in tha case of the eoual potential wells. Ihe expressions are obtained which describe the HUB relaxation and tha BUB second moment at the simultaneous reorientational jumps between both equal and unequal potential wells and also the quadrupole relaxation at the reorientations between unequal wella. She potential barrier values are evaluated for the various types of the reorlentations observed. A1317 Q A1318 187, Of THE lUPnaiTT. ATOUB OS B* iqs rmpmova is V 9 LlBeO^ AID Jlo 1BX ?Hb 8

~~A1319 A1320 OF THE SrcOaWaasDBAIB PHASX » NEW UETHOD OS EEVHUNG CURHICAL SHIFT AND QUAJ3BUTOL I.A.BBH3BE0VA, I.P.A£a~~

perature. Fha» traneitioB to -the lnooamenaurate phaar ocoura where tl , p , r , U f if- . are the coefficients related to without change of the number of iqB-llnae, anl only alight chan- the electric field gradient tensor, and the chemical shift angu- ge of tha elope of temperature depandenoea of •qB-freonanaiea is lar depender.. /2/. obaervwd. However, the broadening of she linea appears taut 2 i20 (2) above Te, and this broadening increases with temperature. Tha lines broadening la proportional to the Iiiunamainarance paraae- when d , f , g - are the coefficients related to chemical tar, end 0— 0 with *-»«J. «ro» the analysis of tbe number of shift tensor values. In a case of these effects superposition, linea it follows that I-? tranaition eeoara according to the too OB line shift may be described as a sum of (1) and (2) ex- pattern 0* I^SaC^, having alallar atruotore /2/t KPnaZ,) -»• pressions. In such a case one can determine the tt and ty coef- »(Pne2,) with a tripling of the lattice parameter 'along a. 80, fiolenta from the three rotations around tbe ortogonal axis at inrina—nalirata phaae appearing la eonueeted with •oftening of one frequency. Then according to tbe aystem of equations the ft , the lattice mode with wave veotor (jf = (i-lf) O-'/i lneoanensurate p , ."• coefficient'may be determined, and tbe wnaors may be with lattice periodicity. High taaparature phase tranaition la 'oonstruotad. The proposed procedure is essential when quadrupole •oot^jenled by the ohange of tha : ' of iqa-linaa and thus nuclei situated in a structure of crystal with defects are stu- tar tha raising of group ayaaetry. died. With a help of the method we have determined electric fiaU gradient and chemical shift tensors for Al27 nuclei in a natural 1. Seweda Sb., Shirolahi X., X.aamoto A., Zakaahlge >., microcllne and albite crystals. •atau a. J. Phyi. Boo. Jav. 43, 2069 (1977) 2. lisgd a., Axe I.D., Shlrane a. Pays. Ber. B15, 4392 (1977) 1, Volkoff O.at. Canad. J. Pbya., v. 31, 820, (1953). 2. Qoraoatanaky* 8.D., Stager C.V. •?• Chem. Phys., v* 46, H 12, •959, (1967). A«21 CXS—TRAS8 inSIBDZBQHBUSaSXOI 'JXD UUVXOB DlMUXQ8*0V PH."* i (n) cnwwuTW BX.~I ms. , M.flH,'I«UI and 8.SEUBHBKXtt, Tnatltute of Ge- neral and Inorganic Cbealetry of tha 088B Aaadeay of 3oien- i 117071. 0888.

The ola-tiana tSereoisceieriaation has been reported /I/ to ooour in the complexes ftlglag (la • CjBjldlB^agHjIBjtaBjlBj). le Save observed the 127I RS epeotra of both ola- and trans- lsoasra of thaaa eoaplaxaa to obtain an lnfonMtlon on tha number of srjratallagrapUeally ind.pendsnt positions of the iodine atoaav The slew formation of orystal lattlee of ols-lsonera le erldenoed S-'j by tha oontinnoua narrowing of raaonanea llnaa observed-for 8ava~ ral hours after preparation of tha sample* (he study of theraolsoaertaatlon prooesa has been carried out by tha hasting of ols-isoaara In atagaa tallowed by the re- oord of the MB apaotia. The results are given as diagraas of J ?, suceesaiTs alterations of the BOB spectra reflecting in detail tha tharaoiaoaerlaatlan prooesa. Thus tha W» data show that the heating of tha eowpl«i:ols-Pt(IPy)2 at 14O«C for 1 hour ia'saf- fioient to Initiate the thermoieonerioatlon whloh then prooeedo andar tba noraal eonditions'right to the full oonreraion into trans-lsoaar. the results for athylaalne and methylaaine oonple- xes have bean aeoounted for tha fbiaatlon of two oryatal modlf 1- oations on synthssla of eiB-laaaMra. The relative- content of tha modifications depends on the preparation eondltlana and way vary with the tine. Both modification!' coexist up to tha conversion of tha ooaplax Into traneooonflgaration although during laoaerlsa— tian their proportions amy alter depending on tba praeading hy- story at tha sample. Several atruoture transfonnations have bwan detected in oia-PtJjdalBj)^ in the teaperatura nngs 1OO-17O°C. Basing on the KB data obtained the oovalent 6-oharsoter of 'the Pt-I bonds has been estimated within the Townes-Dailsy theory approximations for all the complexes studied.

1. Kukushkin, Yu.H. and Poatnikova, E.3. Zh.Prikl.Khia. XUV, 1406 (19T1). Bill B4I2 9B. DIKE 01 TBS PMCMSTM Of SB I STQDT 0T TH1 UORID HTSTKHJSIS 01 IBs * YBBTQ& 01 "itaBmeh 1mtS38&AIB*B«m> SPftClaiUL * Ge>Ba&OZsBmsSIXmSaB0msBBBma^8mfVBKXX|S •SeDmamSZ4M• IHal%Atllt* Of Chi— r,T3ogdan«, BJ.aodirrt.toT. H.G.Ioiln and V^.Stjlnal mlstry of lenlaered State university, lenlngrad 139164 D.S2B Inatltnte of Inolaar Phjaloa, MoaoM Btrta nniTeralty, Moaoo> II72}*, OBSB The mnesbamar sp«tr» of ualexial anperparsmignttio (SI) particles hee boss studied in the ess* whan p/8«1. p la the fre- *ba Mgaatio hratansla of tha hjpaxUna fields was flat qmansy of traneltlen.i of magnetisation veotor • from the region obaarred waan lnraatlgitlng to* poljoijatalllne bslolua wltb tha arownd oae easy axle to another. Si. la the larmor frequency of "5 n%n Maabauar isotope as an Upurity /I/. Ihie phanomanon oon- is aa anieotropy field. The spectrum la given by expression sists la tha inosaasa of tha hjparfina field H for tha 1I9Sn s> elai aftar re»OTal of the ezUmsl Kgnetlo field Bfl. fhe value ABhjst ** * ooaaegnanae of the paniatsaoe of the formed fan map natio s«rnatu». lbs table glvea tha reaolta of a more detailed' investigation of' tha hjateroala in Bo.

B.kOa B Comments Bo-0 Hsa40 kOe hi . !e are the spins of a nucleus in the ground and excited eta- ».a •M5.7 -WO,I 3 19,9 The absorber V-;- -189,2 ».* (foil) with da- tes, 11 Is tha interaction Between the nucleus and tha electro- . -118,3 10,9 6 1,5 magnatiiing lao- ' 27.8 -106 -106 II tori • I magnetic field, (*fg{(p) are i^*** elements of tha rotation opera- «.• 0 tors, a la the preceselon angle of sf. -120,0 -124,8 4.9 5 25,3 • Powdery abaos&er. The model spectra, for re" SP partielea are given in figure »SM koe, 1800*9 sad etf -dashed line), we assume that KtB The hjstereaiu praotiaallj diaaopeara at 28K, which glToo ita tem- have Boltsman distribution, wich depends on «.. ool/kT, where B perature limit. Tha value of |AB|, whioh la a •aaaure of oompati- B a +B nd the oontli la tttbbs energy of the psrtlclea. tion between the looel field, Hloo s o"^ dm lior' " - The aoasbaner spectra' calculated bation of the fan atznotoxe, la large for the absorber with S = I using the dewerete oriemtattaas; model IM at »,X and 27,St. it 48,« aloo is less the oritioal field Ho have symastns lines. The experimental at whioh the rearrangement of tba spiral structure into the fan spectra usually have sssysmotric Unas end one begins. Therefore Bo produces no preferred dlraotton or «egne- onei.tsles to explane thle asaymmstry bj. tisatlon and. causes only tba speetrum ameadng. Its value |a Bhjstl different hypothesis, lor example, H8ff In depends upoa Bo, for Ho«20 feOe at 14,91 it was egpal to 4,6 kOe. the oenter of the particle is not equal to "he Investigation of tha parameters &B and &H^Bt versus that on the aurfaoa. The given calcula- temperature and magnetic field Bo opens a pernpeotlve for a new ex- tions show that the aaeyometry of lines is tremely sensitive Bathed for studying the BBI magnetic struoturas. tha eeaantlal characteristic of Mosebauer fll P.V3ogdanov, S^.Godovikov, M,S.Eoiin and V.S.Shpimil, on spectra of SP partielea when the prec Letters, 26, Bo.4, 327 (1977). eion mmy not be neglected. I2J S.H.Tajlor, U.I.Darby, Pnyaics of rare-earth solids, Chapman and Ball ME, London, 1972. 1. GJllOMBam, phya.Btat.aol.(a>,46,131,197B.

B413 B414 MOSSBiUSE S££CiaOK 0? OFTICAilY BtCIIEB TIKE-RESOLVED MSSOBADEH 6PECTB0SC0PV ! OS InS»57Co CXtStKL Sashklrov ah.8b.,Hbanian i-B. .Parfanor 3.B..Slnyabaki 7.I., E.BIALO and S.XOCH, Institute of Physics of the Estonian Isaaa stsU unlvareitjr, Zaaan, USSR Acadsiy of Sciencea. Tartu 202400, USSR CoBsUexatlame about possibility of tba isflnense of light emission, an parameters of VBaabaaer apeotroB In crystal were made .Time-resolved Kossbsuer trananission spectra of a monocrys- 57 more -then ten Tears ago [1,2] .- However, we are not aware of the tal InS- Co single-line v-source (6 vci) and an absorber 57 2 expazlmante, which confirm this phanoaenon, so far. Na4Fe(CR)e-12H20 (0.2S mg Fe/cm ] for different predetermined lex eSodj thia queition we eeleetei same brightly jhntoeonouc- time intervals have been measured at 295 K. The tijne resolution tim mingl* crystals, which permlted to hope far reoelvlsg eonsi - of the 122 KeV - 14.4 keV delayed-coincidence system is about dexmnlei distortion of lane rolency stalls under effeot of light 4 ns. The width of the time intervals is chosen about- 30 ns. For emlsalOB. «e oazzlad sot MBasbaoax Inraetlgmtions of single crys- comparison time-resolved Mossbauer spectra of a source Co in tal! shawtw •*»•*. ffm Ab/S and JV*wlta 20*5 tMtaieai. Fd metal (5 uCi) under identical csnditiona have been recorded. •BssBamar aseatn. fox each sample ewrw obtained in dark ( the asm. For both eources tvpical modifications in the tranmnission line plat was oostmlned In to opaque eellj and under different illami - shspe (decrease of linewidth with delay, oscillations in the nances, nmsuammx aoeetxa of AAand *h, &>g,£ axe asrrortrioal wings of the line etc.) due to "time-filtering" are observed. doaslat and it Is single line la the oaae of •** . The following differencea are found for the ZnS-57Co source by bpaxlmenta showed that optical excitement lead to the gro - comparison with Co in Pd: 1) line intensity increases cansids- wing of qusdzupola splitting and to lowering of HBesbauor shift, ' rsbly slower aa time increases and 2) a time-dependent shift of i.e. electrical density and ayjsnetry of electric field on the MBs- tne line poaition is observed. These features show a local "heat.-* abaner nuelaus are changed under effect of light odeaion. ing", i.e. the increased values of the mean square amplitude and velocity of vibration at the Fe sites in ZnS, which accompa- 1. Berauker I.B., rovarski T.I. Pls'ma zh. Bksp. near, fix nies the banding rearrangement of iron iona with their environ- 2, 286, 196$. ment after the 57Co nuclear decay events preceding tha Mossbauer 2. Basbklrov Sb.3h., Sadikow S.I. Ela'ma Zh.Baxp.Ineor.H.1 transition. The relaxation time of this rearrangement is estima- 2, 240, 1966. ted to be shout SO ns. Most probably the time-dependent ahift of the line position is caused by changes in the thermel shift or/and in the isomer ehif t during this relsxation. B421 B122 Tax ifRCT or TBI UTVUTIOH on Tm mat wFzmmcE or T8E nq HBOBf BilSI QBDBB IHTBSTIOiMai IB BOMB B0UITICB8 BI HUIB TUX3ITKHS III » nO-UmiL SPIH SYSTEM. QIXFB .: I.K.HHIB1SS and T. B, yimnHgHIaOT. Pedagogical Institute of H Bomcalno mtn aslardi - Utitu o dl Nslca dell'Univeralte. Fera, Perm 614001, USSR, sad Dhinmtr at Pern, Palermo,Italy. Pen 614005, 0B8B «« nave detected transient effects in the non lin«*r response a method is proposed of using experiaontsl data on the of a puumnllc spin system excited by a step-ewdulpted rsdi SB Use shape and line with concentration dependence to study stioa at double-au&ntua (DQ) resonance with a spin transition. the short range ordering of magnetic ions In solid solutions. In the experiments tbe DQ transitions lure monitored by measurins; The second and fourth momenta of the line shape function hare the intensity of the Second Harmonic (8H) which is emitted by been expressed in terms of the site occupation probabilities , the spin system a* a result of the DQ dumps from the ground to for the nearest coordination sphere in the cases of weak end the (Kited level. The SB spectra,detected by measuring; the strong exchange interaction. In both cases end for different line shape functions problems of two types have been solvedi emitted intensity IggttH) as « function of the static field H the concentration dependence of line shape parameters has been and at a fixed time delay ta after turning on the pump poier, obtained assuming the uniform site oeeupation probability i • appear to depend of the time tat evolving from a bell-shaped distribution throughout the concentration range is question) line to a line vith a central dip and t«o aymsetrical maxima, and the probabilistic description of the magnetic ion distribution has been oonstruotad on the basis, of experineatsl data on. when ta is varied from t.-0 to a few msecs. The'experlmental the parameters above Mentioned* The method proposed may be curves of the emitted intensity IggU) as recorded at a fixed used for the short range order investigations in single cry- value of Baare fitted by decreasing exponential lavs with charac_ stals, powders, and glasses. If the line shape function in teristic parameters which depend of the detuning from the DQ sou concrete ease is known, this aethod is sore suitable for resonance and of the pump power level. Bath the changes in the tbe investigations mentioned than the numerical one previously emission spectra and tha time dependence of 1 are shown to proposed by the authors /V. i be caused by the saturation of the spin system induced by tbe 1. Henner.K., EhaposhniJcoT, 1., Bonis.S., and Soxdoe,B. Proc. K) absorption processes. This interpretation is supported by Xn-th Congress Ampere, Heidelberg, 1976, p. 620. the results of a sesiclassical calculation of I in which the

•piD «jrstea from its Initial theraal equilibrium toward a new stationary state saturated by the DQ transitions. Finally,we suggest toat from the experimental tiu dependence of I™ OH informations on the internal structure of the Magnetic reso-

~~6123 THE MEANING OF THE DEGREE OF HYBRIDIZATION IN PARAMAGNETIC CLUSTERS M.MORENO. Departamento de FSsica Fundamental, Facultad de Ciencias, Santander, SPAIN.~~

~~Despite of the number of data on the degree of hybridization~~

CD.H) fs/.%- of ligsnd atoms, its meaning and its relation with cpvalency is not well understood. Simple and widely used assumptions such as sp" (n=Z,3) hybridization normally fail to explain the experimental results. In order to overcome this problem, we propose a rule, based on general theoretical grounds, which essentially implies that , for a given ligand, the D.H must be maximum in an "ionic situation", shoving a tendency to decrease when coval«ncy increases . This statement is based on the fact that bonding is mainly made

through np-orbitals as deduced from the large Hpp-HSB difference in ligand atoms (lying between 12 and 24 e.v typically) and is well verified by the series of analysed complexes. Also as a significant application of this rule, we are now able to understand

the puzzling feature showed by D2n complexes, with two xnequiva- lent bonds of the same ligand atom Cauch as in KjCuFi. , CSCUCI3 or copper Tutton salts), where the shorter bond has always a D.H lower than that of the larger one.

~~The value of fB is also analysed following a simple H.O. model which qualitatively explains the experimental values. The im-~~

portance of the core polarization into the determination of fs is estimated, showing that it produces a contribution to the isotropic s.h.f constant which, in the best case, is about seven times lower than the experimental value. B1301 B4302 II ATTL1CATI0I 07 MOSSBAOTH SnCtROSCOFT H06SBAYEB IHVBSTISiTICma OF HICKEL FKHHIT ADD FSHHIO 57 oi »« roa m nusnoaxioi or B«. asxas AWER HEOBAHICAL QRHTOIMG G.S.BSlOZHiSHI, T.1.QTW30VITCH. S.T.LDBABSXII, I.V.WJRA3BKI5, Tu.F.IHIHCH, Institute of Chemistry of Leningrad Stata Univer- Ju.T.PlVUmmi. 7.V.B0LDYEEV and B.G.AWAHMOV, Institute of sity. Leningrad 199164, 0838. Physico-chemical Principles of Processing of Saw Hinaral Ma- terials, Siberian Branch, Academy of Sciences, Novosibirsk The stata of la impurity atoas in Ba baa ban inve«tigat«d. 6J0O9I, USSB The concentration or re hu not exceeded 2'10~2 at *. The klna- G.H.BKLOZBBSSII and V.H.dTSOTICU, State University, Leningrad tica of formation and aolution of Pe-oontaining phases and also I99I64, USSR the modification of cryetallograpble aniaotropy (taxtura) of Be samplea has baan atudled during their ieothermioal annealing. The systems with a regular structure and a developed sur- At least two nonaqual BtBtea of face are particular interest for superparamagnatisia investiga- Fa atoms are found. The first state tions. The mechanical grinding in the centrifugal planetary mills iS corresponds to thoss atoms of Fe, is a perspective metnoa in contrast to other methods of prepara- i« .which substitute 'the Ba atoms in tion of small particles /1,2/, tha hep lattice. The aacond ona Ferric oxide (J, - Ze2Qj) end nickel ferrit' (SiSe^Oj,) were .*• corrasponds to different Fa con- investigated by the HosBbsyer method after mechanical grinding 1 tslning lntsmetsllits /1/. in centrifugal planetary mills. The properties of the investiga- ff, g A»""'»'Hitc changes tha ratio of ted substances ware interpreted as superparamagnetic. f 02 5 re atoms in the different states By the analysis of the cation distribution in nickel ferrit I (sss fig.). The Una which corres- it is shown that about 13* of ferrum B-ions acquire nafnetic A- B pesds to intermetellita has a com- neighbours of a new type, and, as a result, H „ decreases by plicated profile, which depands on 50 kOe. It allows us to consider them to be diameguetic fit and annealing temperature. The amount to associate them with the absence of A-ions in tha surface lay- o son mri of la atoas in thlB state reaches er. Thus the estimated sizes of such particles will agree with its maximum at 650° C. the data on the analysis of the superparamagnetic spectra obtai- the stud; of the Fe atoms, which ned. substitute Be atoms in tha hpc lattice .enables ona to evaluate tha degree of texture (see fig.) 1. Boldyrsv, V.7., Awakumov.E.G. Usp.Khim. 40, 1855 (1971). and the distribution function, describing tha probability of the 2. Awakumov.E.Q., Krechman,A.F., llarx.G.L., Vamec,V.A. Izv. given orientation of crystallites* Sib.otd.AH 3SSH, ser.khim., D 4, 5 (1977). It-has been.found that tha BTG sign on Fe nuclei in this state }. Baschkirov,S.S., Kakhanav.R.A., Idberman.A.V., Sinijvsckii.V.I. is positive. Fis.tver.tela 18, 3536 (1976). The degree oi texture (a ) and the relative content of inter- metallitea (j ) dependence on annealing temperature is given on *he figure. 1. Janot C. and Gilbert G. Phil. Hag. 27, 545 (1973)

B1303 A FERRHUGKBTIC RESOMANCE AND HQSSBAUER SFECTROSCOPIC PARAMAGNETIC RESONANCE AND MOSSBAUER EFFECT STUDIES ON STUDY ON THE FORHAIION AND SUFERPARAMAGNETISM OF SUPPOR- 2oFe2Oj8o[3B203( loo-xlPbOxGeOj] GLASSES TED IRON OXIDES w. muBMWP p. SCHMIDT, E.DDiao. I JUUJEtEWi end I.BIBICU, National center of Institute of Physical Chemistry, University of Hamburg, Physics, P.O.Box 5206, Bu&arest, Romania Laufgraben 24, D-200O Hamburg 13, FRC C.N. BELOZERSKII and K. KASAKOV, Leningrad Stata UnivBrsity, Chem. Dept., The Hosabauer effect measurements on zFe2o3(l-z)[Pbo.3B2oJ 199164, Leningrad, USSR glasses showed a high value of the ratio, r, between the number 2+ 3 Highly dispersed iron oxides were prepared by ferric ion of F« ions and Fa * ones, which is dependant on cofiosition impregnation and dehydration on silica supports and by ferrous / 1 /. In order to obtain further information on the part played hydroxide precipitation inside the cavities of faujasite type by the composition or melting temperature on the ratio r we have zeolites, followed by oxidation and dehydration under condi- studied the glass system with constant F^O^ content, tha PbO tions preserving tils zeolite structure. The formation of being gradually replaced by ra^ up to x • 25 mol%. Two sets of was proved by ferrimagnetic resonance' at g»2.3(300K),NGR and simple prepared at 1250°C and 11SO°C, respectively were studied. magnetization measurements. The temperature dependence of the The electron microscope measurements show In both cases that these are in anocphous state. For the samples obtained at 1250°c, anisotropy constant was obtained from ferrimagnetic resonance m data. Using these valuas, the particle size distribution could the ratio r decreases continuously from r 0.7 for x • 0. The ++ be derived from the MSI spectra. The values were compared with quantity of Fe ions in glasses prepared at lower temperatures. particle sizes estimated by analyzing the magnetization curves. is very small.

~~Even with calcination at 1100-1250 K small amounts of T-C«2°3 The EPR msasnrements show the presence of 9 * 6.0; 4.20 and~~

~~(on SiO2 supports less than 1)4 as was evidenced from the satu- 2.00 zesonance. The temperature dependence of the inverse of line~~

~~ration magnetization values) war* detected, but a-Fo2o, is intensities of g » 4.20 resonance follows a Curie law, while in~~

~~found preferably. In tha o-Fe203 saaplas the SSR absorption at case of g • 2.00 a Curie-weisi behaviour is observed. This is a~~

g=2.3(30CK) was attributed to the traces of r-Fe20j. This transi- further evidence that g - 4.20 resonance is due to the isolated tion shows the same temperature dependence of the g and H values. Fe ions, while g • 2.00 is doe to ferric ions 'disposed in a No other transition, e.g. suparparamagnetie resonance as in the cluster. The compos Itlon dependence of the intensity of resonance r~F*2°3 tamP1" could be detected in this field region. From lines is In agreement with the results of KB studies. Possible

the a-Fo20j samples Hist spectra were taken below and above the explanations of the experimental results are given. low temperature magnetic transition (KOR1B temperature). From ths transition to the superparanagnetiam the particle size distribution was obtained. The motion pf the magnetization I.Ardelaan, E.B\EZO and I.Pop, Solid State Cows. 13, 211 vector of the superparaaagmtle particles was discussed in (1976). tarns of the model of discrete orientations HDO and a modal based on modification of HDO Inntnoing some features of diffusion mechanism of transition. Si" / B1305. B4306 IHB ESSBABOB Q» QJIASBOFOIB BraBUOf MBS n or m BHAUHOI WDD IDMHAHISII IB THE maiTATiYJS rjana THI nmna or amsaiai tnS&TOV MMSBAOIR StKOk .: SPKTBOBCOPI Of 125I i»B HTJOUJB QUDBatOEB T.I.OOIBaSSai, B.A.STDKAI.T.I.PBUSSAKOV HAIOI or iwi • iMtltute of Ohaadoal rhjraloa U88B Aoadaar af Solanoaa, L.o.Bhtan*ov. T.V.Kbxapov, T.A.Babushkina, Institute for Biophysics, Ministry of Health TJS3H UnlToraity of Tachnology, Halalnkl, Knland • - ' Mosooe 123182, TJ8SR The chemical effects nuclear decay In sobstanoe are a Die eattaton Msaabauer apaetre of oobalt terma/anidaa mre ooabination of nuclear, atomic and molecule processes ft, 2] obtalnad in tha taaparatura zange 10 • BO°K. Ste eetlaations of If the affected atom was aoabined In a molecule and the systea xmta eooatanta of oonroralon of tha unatabla "tumbull blue*, create! after tha nuelaar decay of ^Oo to the eteble Truaatan la a gas or, possibly, even in a liquid radioactive decay will N lead to a oouloabic explosion because of the rapulaive forces, blua , wan aarzlad out. It !• found that tha rate oonatanta nach aiiaing between tba different aiadlarly-oharged parts of the certain plateau ralua balm T~XpX. Sola raault teatlfla* the aolecule [5] . In a aolid, the Auger cascade will be very saall oantdbution of electron tBBMl meahanlaw to ralaxatloii pro- and charge of the affected atom will depend on the nature of o»

B4307 A 13 BK308 USQUEHCHED ORBITAL UOBEHT OH Co AHD B»EBTtIE 57 THE CONTRIBUTION OF THE PHONON-MAGNON INTERACTION IN nSiLB OK Jt U EHUT£ Pd(r.,Oo) AUOIS THE SHIFT. T.A.ilimiAKOT.E.g.UBIHSmA. A.Iu.PENTIB, V.S.SifflStl, Inatituta of Huclear Pnaaiea, lioaeow Stata UnlTaraltr, Moscow S. Ram-Banal Cento da Ejhrdlo, Nudeam, UNMI II7234, D3SB Clmite Exterior, C.U. Hialco20, D.F. Xoaabanar atudiaa of a Pd(' Co) source containing leae toan 0.2 at.* of Ye lopuritiea hare been performed to investigate the D.SI.P.I .... origin of positive hyperfina field on Co Impurities in Pd. The UnlvenRy of Uanchotar Sdwiter Uboratorj UtadlSEIU spectra obtained at 40 - 50 ml, when nuelaar polarisation la «a- nlfeeted, Bare baan analysed. Xoe Intensity ratios of different" spectral components venue temperature ere shown In the figure. Thep naa taken late account Solid line. I iid 2 correspond to In order lo fit the Seta of the Iheraal ibjft of die aHusauar ipaotra the ratios »^ A.|^ and f|^ /fj_j respectively, calculated with allow- of TbF,2 rrom 273"K to 800'K thUneiWnlglitasplalnamall ance for orHy aagnatic iyperflne S9 citcontlruttr at (he Curie ejlnt. interaction on Co nuclei, w&areaa daanad lines are drawn taking Into account also quaflrupole Interaction reeultiug from one d-el«ctron In a atata m-2. Sxperloental points give the Bagnltude of this interaction corresponding to about 0.8 d-eleotron. Tnerefors the poaitlvs aign of the hjrperflne field on Co nuclei 30 40 ia due to a large contribution fras "•nf tha unauanc&ed orbital aoaant is aooord with the data obtained fron HHE and aagnetoraaiataBoe anlaotropy naaaurementa fi.-l7. The spectra obtained at teapera- turee from hyperlow to 4.2'I and Is external magnetic fielda up ' to 3 kOe show that the magnetic transition temperature ilffera for different groupe of lapnrlty atowai hyperflae fields on re nuclei attain rapidly large oagnltudes and have a certain dia- pereian.

1. latayama et a., J.PSys.Soc^.psn 40,429 (1976). 2. I* Bang Ihoi at al., J.Pnys. 16, £197 (1976). 3. Sazoassl 3., Caapbsll I.A. and Tert A., 3ol.3t.Co». 21, 269 (1977). I'i B«09 V_/ B1310 J^ ,/^ 01 IBB THBuKf Of 1MB MOB 8PECTBA MDSSBAUER STUDY OP RADIATION DEFECTS INTERACTIONS Of MUBD-VALBICS CQKOUSDS WITH IMPURITY IRON ATONE IN NEUTRON IRRADIATED MOLYBDENUM giiiKMHafl Institute of Chemistry of the Moldavian A.ZHETBAEV. SH.IBRAQ1MOV and A^HOKANOV, InaUlute -Ata 480082, USSR

The nonaeoular stochastic theory of lint shape IM ia The Interactions o< point defects induced in molybdenuia by neutron azttadad on tha SOB apeotn of mixed-valence compounds. A sub- irradiation in the reactor active zone with impurity iron atoms were inves- stantial feature of the propoaed nodal ia tha involving of not tigated. 0BI7 electric field gradient (SPG) value fluctuations on tha The prows* °f Interstitial atom trapping and detropping by Mosabauer Buolcua of Hoaebauer atom but also ita direction fluotuationa atoms durlrv Isohronal aruwaling was observed. 'during the change of tha valanoa atata. Acaount of th* BFG re- The impurity-Interstitial pairs formation 1» expressed on spectra in tha orlantation makaa it poaaibla to daaorib* tha ngularitlta in form of an additional "defect peak", the intensity of which deperals on an- tha apaotrm bahariour at high temperature limit. Xha Una nealing conditions* ITie investigations were performed in the wide tempera- m ahapaa for a number of la cluster compounds HI ara calculated ture range tram ??°K with varied irradiation doses* on tha ban of tha obtained, general foiuulse. Ihe probabilitiis Some conclusions were drawn about fee mechanism of,the point defect of electron transfer and the anglaa between the HPO symmetry formation and mobility and crystal field parameters in Immediate proximity to 'lify. axea in tao yalenoe atatea are determined fni oomparieon of them were estimated. tha theoretical and experimental apeotra. Ihe account of the BFO rotation ia ahowx to be of eaaentiel iapor*anoc for el cor- reot deterainatian of the eleotron transfer probabilitiea.

~~1. B.B.B2.une, Ibys.Hev., 174.. 351(1908) ' 2. i.V.Ablov, 3.A.Borehoh, K.I.Iurts, S.A.BobkoTa, V.I.Ooldon- akiii B.A.3tukan, Proo.Intern. Conf, on Hoeabauer Spcctro- acopy, Bucharaet 1977 •~~

AS B4311 B1312 B 1U Mb'SSBAUBR EFFECT OP Sn M1GHEXXC 3R1HSB0H1USX0B IB* IN FERROMAGNETIC CrOj Kb.I.«mir»banov,Sh.«.illeT,L.K, K.P. Mbsfenovk S.I Reiasn Institute of Fhyslce, the Sagheetan Branch of the InatUuta cl Huclew Physics, Moscow stale UrsversUy: ' of Sciences of the \ r 11723*, USSR.- Msgmetlc phase tzassitlon aasoelated with fluctuation of alttc- tlwa magnetic Iiol4 H^jj _ on !•'* nuclei was founa tiy HSssoauer Moaebeuer effect have been eluded in ferromagnetic CrO2 study of lorrlto ai aC6^ ^*^D CV7^*IC) •* *t=212"«« B» UOB - deped srith 0.1)4 atomic * of U9Sn The values of Iha quadrupole O| t 4 3 bauer apaatrom of this f errlte above Tt snows three hjperf lne p«- epHBJng and isomer ehllt (relative to Ihe source Ba SnO3 ) are In ttama. Im af them, B. end a,, belong to aagaetlc nonaautTaJant the usual range for Sn4* In oxidei aB - 0.6 mm/s , octahedral sites, eitX the tUra k~ to the tetrahedral one. It oB • *' 0.1* mm/a. Magnetic aplilfrej at low temperature corre- 119 ahold ba moted tfaat B^-sttblattice arises owing to tns replsceaent sponds 1o very sirens internal fields at Sn nuclei: 2+ S of Ii ions by dleaaenetlo Cd *iojm in faxrite BJJe2o4. Ihe oute- 390 kOa. The sMSnltuda of in CrO, is int rmost eboorption HzaaC1and6) of tho ^-slte pattern [f =1.O6lo.O5 siamficanUy larger then that in any other magnetic oxide and aa/aee is much broader tnaa thoae of B,«nd k patterns (n?=f'= °-5^ approachea the value of H^"' in chalcogenide spinels O.OSas/see). Ibis is evident of the fluctuation /V of Talon of ( —800 kOe ), which are the largest so far observed by effactive aagnetis field B^ on fa34 Me^Mu* .fleet of "'sn. lei in B^-aublattloe. Proper * la known, that Internal fields on dlanagneUc nuclei are eotlaatton of the fluctuation leads

mainly due to the Fermi contact Interaction. Bearing in mind Ihe to AH^=}6i3K0e. it Tt B1-aublat- ,(Sn) value of Ihe leoanr shift Iha enhancement of H In CrO, int tlce is broken lute B.,., and B1 £ could not be explained by covalent bonding, aa In case of with tha snbsaqueat cessation of chaleogsnide spinels, end should be due to Ihe Increase of the fluctuation process of theH^. i apnvpolerlaoHon, of s election, of ImpurUy alone. Such effect Ill above said testifies . -a di- can be understood If in caee of CrO2 beside. Ihe usual supei- "* °" •"•"»""••»»« xtet pjiationahlp of magnetic tra- exchmnge Interaction responslbla for magneUc ordering In cgddee, nsformation with the fluctuation ease other mechanism, such as caUon-cetlon exchange la present. of H| value. -

~~The temperature dependence of E^t Is shown in Flg.1. As can be Sean, B.-aubUttioa caaubstituted by Cdz+ is not imvolved in the~~

phase tranaitian. Xxohenge intezmetlcns at T>Tt betweea B. 1 2 B1 2 aublattioae m assumed to be realised by means of Cd * • allmm to cosaldar thea as on* B^-sublsttlca. And the fluctuation of is indicative of • relaxation nature of aba exchange intar-

Beferenoeai IV. BJJvana. Uosabajer Bffsot HetbodolOKy, 1, 1», C1968). B131J BH3M sl B UDSSBAUBR C0HVSB3I0I 3KCT80SC0PX Of IBS fflGH-KSWESW •BsSBAUaS STUDY 01 AMORPHOUS »«4o 4O 2O < SOLID 3IAIB rSBTUBBAIlOBS OLlflS A.Y.KITIH. G.P.eHUGUHOVA, Ifcysieo-Teohnioal Institute of the R.A.IUJMOT, A;ytlgM» and P.G.VAOHOY, Pnysieo-feehnionl Academy or Sciences of the USSR.'aasan 420023, USSR Institute of th* Academy of Sciences of the U3SB, Kazan 420029, USSR Extensive experimental stud ten of the surface solid state anr th< praperlies via the Hgasbauar apectroscojy of tba inner-shell Wssbausr spectra of th* '•^gHi^aja ^'oP'returo conversion alectrona have aet the problem of creating such a range 4.2 to 300 K are investigated. The sample was supplied theory which soul* enable to describe both static and dynamic by Dr.H.H.Iibermann /the university of Pennsylvania, USA/. phenomena, using a density matrix method of the electron-nuclear Measurements wer* oarried out on a ribbon sample C25OaO.BaO.O3S =ystea, the kinetic equations for the matrix element* af the mm). Using the ribbon pieces, aet parallel!/, th* absorber aensity matrix and the formula for the conversion electrons in- Cl2x12 BB) was prepared. Th* KOMbeuer spectra represented such tensity are obtained. In this method we nave uned the fact that spectra which wtr* chnracteriatic for amorphous solutions /1/ with broad line* caused by a random scatter of nyperflne fields the uatrix element for the conversion nuclear transitions da- ST aunda ueaicly on the external perturbations. It is shown that on the fb nuclei. In contrast to /I/, th* hyperfina fields thou&h conversion is a scattering proceaa, its spectrum is si- Distribution was described only by the Gaussian distribution milar to a uaasbauer absorption spectrum. lo illustrate it,the with a larger half-width to a high-field side. The distribution detection method of the {-magnetic resonance ia considered/1/. widths wer* &1 .33 kOe, &2-39k0«, respectively. It ia motion- The analysis of the spectrum of {-magnetic resonance ia carried ed that the hyperfina fialds distribution undergoes only slight out 03 tha Fe57 nuclei in iron. She possibility to study magne- changes Up to low temperatures. Using an angular dependence of tic surface phenomena via this method is shown. Ultrasonic modu- the intensities of the KBasbauer spectrum components, it ia lation of j-redistion by tne Baylaigtt surface waves ia consi- shown that the samples have magnetic snisotropy witb a light dered. His shown that the conversion electron detection method magnetisation axis directed slog a long aide of th* ribbon. etui be usec. to registrste the Bayleigh waves in a wide frequency range. 1. Sharon, T.B., Tsuei, C.C., Phys.Rev. 3 B, 104? (1372).

~~1. Mitia, A.V. Zh. Kksp. Teor. H.E- 52, 1536 (1967).~~

~~B4315 ABOUT PE1TUHES 07 DU3LEAR SHS-ECHO DE9XCTI0H Si A13ULAB CORBELAHOaS 07 BUCLBAH RADIAHOB l.F.SEAKEKDBAIOTA Kazan State Fedaeoeical Institute, Eaxaa 420 021 .USSR~~

fbeoreticol conciderstiOB anowsdt that auclesr spin eviction f;SE) by means of perturbed angular correlations o.' nuclear radiation has s nmiber of specific features. Firut, He natural time scale is defined ia th* fAC experisent, th£ ro- sent of oriented nuclei appearance being fixed by registrarion of a preceding radiation or a beem pulse. Second, nuclear spin- system evolution is displayed in the oscillations of the DFAC curve, the inhonogeniety of static fields in the specimen des- isoying them. But the pulsed rf field may restore the oscillating character ot the DEAC curve en tie tlm^-interval of the or- osr of reverailjls relaxation time Tj . Third, in PAO detected IKS otctistical tensors p). of higher ranks Oii$ $.21 3?° registered, thsn in ths classical USE metiod. This causes the appearance of extra moments of formation of DBS signal in SAC. But either geometry of PAC^experiment is sensible co sehCTiaur of certain tensors J>q • fourth, essential tie dependence on the geometry of experiment aakes passible the one-pulsed ejnitotion of IISE signal .which is of special In- terest. Fifth, generally PAC-ESS signal ia sensible to the pulsed field phase,because of that the latter has to be fixed. But there exist certain coses of HSB excitation in PAO with an arbitrary 7? field phase,e.g.in strong magnetics. And finally, PA0-1EE is a aicroscopie method, registering radiation, emitted by each nucleus ia the definite direction, the number of uti- lized nuclei in the specimen is conaiderAbly lower than ia clns- sical ."I3S method.

IX V BWOi BVKH COMBINES R330Ki?CE IS SBaCCOKDUCIORS . | \ /CYCLOIBOI ra&OUNCE OF ELECTBCNS JS Xi 44 I.X.8ASBBA,L.D.landau Institute for Theoretical Physics, -fl i^J AT HYBBOSTATIO PSEESUSB. Academy of Sciences of TJSSR,llDaeow,11733»,B3SR. I Koahelev O.S.. Sapcin W.H., Sapeina T.H. 8pln-orbit coupling in soalcoaductors results In coDji- Physics Dopartaent, Moscow state University, 117254 USSR. nad resonanoe (OR) I eleetroa-dipola transitions with tha cuange Cyclotron resonance of electrons in hydrostatically pressed of the electron spin state /I/. Tneae transitions are especial- Xn, 4£ at 4,2"K was investigated. The concentration and mobility ly atrong fas.' bead carriers and ara caused, a; tta divergence of electrons at 77*K ware 5.7 101} co"' and 5.2 1O5 cm2/v see of band* near toe eymsatry point dua to the absence of Inver- raspectlvely. The backward wave ;ube with wave length of 0.55 mm sion eaatar or to tha non-^iarabolieity of bands, -m CR frequ- aa & source was used. The -transmission of the aample in the encies coincide with taa spin-flip transition frequency or taa Faraday configuration was measured, the transition temperature combinational cyclotron-spin frequencies. The CB intensity may of the 4*1 film to superconduction state was used for estimating exceed the Intensity of the usual BR by many orders of oagni.- the stress value. tude. Tor eleatrons in iapurity centara CR ia relatively wea- It was established, that as tha pressure (P) was increased kar dua to cancellation caused by time inversion aymutry.out from nn to 2 kbax the aaxdna of cyclotron resonance line shift- ia alas observable,especially in strong magnetic f ialda. ed at the value 220210 oarst in the direction of higher field. There ara alao son OR wcoanisas, specific namely for impurity This eorreaponds to m'dm/dP = 0.055* 0.07 kbar"1 where/?) centers. Tary interesting ia the effect of strong impurity Is the effective mass of electrons. Using the Kein model it was scattering on tie CB with band carriers. This scattering signi- foond, that UE/UP - 13 10"6 ev bar"1, where £ is the ficantly affects tha OR line Intensity, unlike the BSR where forbidden gap value. The founded data of d.E/dP corresponds it affacts tie Una shape only. to the value of ( /£T- /7 ) 10"6 ev bar"1, measured earlier by In tha paper both tha discussion of basic concepta of taa another methods (see for example /1,2/)> combined resonance and a short review of tha experioaatal data will ba given. 1. B.a.Abduvahidov, A.S.Woliovf, W.tf.Galavanov. Pli. Tekh. Poluprov. i,, 1409, (1973). l.Reahba.B.I, £o-r.»js. - Uspekhi 7,aaj (1965). 2. R.N.Sirota, W.B.Schipilo. Til. Tekh. poluprov. i, 82}, (1968).

BW3 SDRHUJHITT OF BK0H1BCS OF CARBISBS IK SEaCONDUCTOB IN VHP PHASE UUB3ITIOHS IS TIO-DIKBIISIOHUi ELECTSOH-HOLE SYSTEMS IN 1UGKBHC KESUE HIGH HiGHEITC FIELDS AND B£EIH EFFECT OH C2CL0TRCN l.I.KATS. Salantitic-Basearoh Institute for Uechanics and HEaosucE Physics. Saratov 410601, U3SE. l.V.LBUUUi and Yu.B.LQ3DVIK. Institute of Spectroscopy Acaiieicj The electrical conductivity tensor af the semiconductor elec- of Scienoes, H2O92, Moscow obi., Iroltalt, USSR tron plasma in homogeneous external alternating magnetic field 2 was calculated In series workJ' JIn this ca3e exhibits a series There are considered quasi-two-dimensional electron-hole (e-h) of si&gaiarifeleBs cyclotron resonance seams to be generally modi- systems (quantized films, layered semiconductors, etc) in trans- fied due to the alternating magnetic field component, the Hall verse magnetic fields at r^CWeH)1'2 much smaller than the ef-

effect and magaetoreslatanca and energy absorption is generally fective Bohr radiuB aQ< Iwo-dlnens3,onal density n$1/2/Trg, so an oscillating fuliotion of amplitude magnetic field. In present that all the particles are at the lowest Landau level - the no- notice take-a view of tbes singularities of phenomenons. tion is Nsero-dimensionalN. By means of the temperature diagram She calculation of effects stipulated of alternating magnetic technique the e-h plasma.themodynamic potentionals have been de-

field is carried out on the basis of general expression obtained termined. Por temperatures T«B0/4 the 1-st order transition can for function of the carrier distribution in homogeneous semicon- occur with the e-h liquid drops formation /I/ with the bound 1/2 2 ductor plaoed is Harmonically varying in time orthogonal electric energy (per e-h pair) X0-(«-/2) e /e rK ( £ ia the dielectric and magnetic fields. It is shown that the nigh frequency magnetic constant). A possibility of the 2nd order transitions witfc e-h

field exerts considerable influence, when -*%^i- (Si - magnetic coupling has also been investigated. For KID/4 the 2nd order field frequency, 5 - relaxation frequency}. The change in the transitions occur at low density froa the e-h gas to the exci to- magnetareclatance depending on the amplitude of alternating mag- nic phase and with density increasing from the excitonic phase to

natie field has an oscillating character* A new method for Ut6 tha a-h liquid. In the tenth order on rH/a0 the 1st order tran- free charge carrier concentration and mobility measurements, when sition iaoterms, straightened according to the Maxwell rule,coin- the sample of semiconductor placed in SC and VB? magnetic fields side completely with the 2nd order transitions ieothexms. It is

is discussed. connected with the fact that with the accuracy rH/aQ the interac- Bis study of the behaviour of the cyclotron and gibrld fre- tion between axoitona proxee to be e'aae^t, so the xeTo-dimenBional quencies as function of amplitude and frequencies or magnetic liquid can be considered ma "stuck" excitons. On taking into ac- field H= He+HijU&Sit , «hose variable component ii parallel count small corrections one obtains a slight difference to the stationary one. also the problem of the transformation of ~0.1(rH/a0)B0 between tha energies of the excitonic and the drops monochromatic .signal with a frequency 00 to components ld+aQ states. Since this difference is extremely low, weak neglected ef- (ft"***-) fects - almost with no changing these states - can make one of these states more advantageous. Being almost coinciding thermodl- She enerlments made in the magnetic field loon of the rectan- naalcally the states can be differentialed by their cyclotron regular waveguide. A satisfactory coincidence of calculated and sonance spectre. In the drop state there appear two lines in the experimental data is observed, 'file possibility of applying the epectrm corresponding to the liquid and gaseous phases while in described effects for the development of measurer of 7HF magnetic the uxoitonic state there ia only ens line. In ell the ceeeB the fields and lnertialess power pickup in centimeter and millimeter line shift from eg/mo is about B ~H1/2. wave ranges la disc used. fl 1. loogovoy 7.H. liT.vuiov. Badiofic. VI. 69f -")£}). /I/. I.V.terner ft Tu.l.loiovik, Sol.St.Commun. 22, 453 '1977); 2. Kate L.I., Bhesnter D.Eh. Izv.vusov.aadio^j.zni. 405(1974). XD.Bkwp.Teor.Fil. 21, 274 (1573). V

BW05. - B4406 CYCLOTRON RESONANCE OF ELECTRONS IN ZaTe or moron Atnaims or OHEABTC (p TYPE SEMICONDUCTOR) • C0MPOOHDS OH I01IIUII0H POTENTIALS AND STRUCTURE ' i.mppax. R.FIKVER and D.MBI0E8, Tartu State University, *• GBIJNEAU Tartu 202400, and Institute of Cybernetics of the Estonian Academy of Sciences, Tallinn 200001, UBBR Univerelto' P. at M. CurlSi Laberatoire do Lumlnescsnce Tour 13. 4 place Juaaleu, 75230 Pmrli Cedes 05 France t I. The analysts of the dependence of the Ion cyclotron resonance gas phase proton affinities (PA) /1,2/ on the correspond- J. F. GALLAND. K. SAMnXADAYAK ing lonlsatlon potentlale (IP) /3/ has been made for various C. E. N. G., Dlpartenient da Recherche Fondamantale classes of organic compounds (katones, alcohols, esters, ethers, , B. P. 85. 38M1 Grenoble Ceoex, Fnmi amides, earboxylic acida, nltrlles, amines). Hather general linear relationship holds 1 W* have observed In XnTe single crystals (p type semiconductor) PA • a + b IP , (1) cyclotron nmuia signal of electroaa M Xbsnd (9 GHs) and Ki bud where slope b - -0.710.1 for all classes of compounds and inter- (35 GHs) frequencies using conventional electron paramagnetic reaounce cept a varies from class to class, •qulpra«nt. The conductian elactrona are craated by ittnnilnaUon of the II. Experimental PA values of more than 150 compounds were Interpreted In terms of aamlempirlcel scr LCAO CHDO/2 treatment. cryital with U|ht wboie anaigr '• Urf er than the band gap. Within various classes of compounds the former can be predicted We cUtcott why the aignal t'a attributed to a c^clatraa'reaisance - by the latter hf .the following relationship algnaX and net to a. paramagnetic aignaU Maxp • e • d PA,^ , (2) The lignal ia laotropie and the effective tnaaa of the electrona (oxprea- where o and d characterise the given series of compounds. sed in unita ol the free electron inaaa) ia 0.12. on the ether hand, within sarlea of structurally similar compounds X - Y (where X la substltuent and Y protonatlon canter) We alao deduce from the reaonance Une ahape the coUiaion time and PA values depend on Inductive and resonance characteristics and the mobilirf of the elactrena (of the order of 10* cm2 V"1 a'1 at liquid polarliabillty of the substltuent X according to the 'equation . helium temperature) : we.repon their variation with temperature. PA - AV. +. Bcr*._(X,) + Co2«R|Xi }• D4R,.(Xj, , (3) where Ag, B, c, and D are reaction Constanta, 0" "(X) "R(X) Taft Inductive and reaonance constants, aR(](, - the molecular refraction of the eubstltuent X (reletlve to methyl group). 1. Molf, J.F., staley, R.B., Xoppel, I., Taagepera, H., Mclver, R.T., Beauehamp, J.L. and Tatt, R.w. J. Am. Chem. Soc. 99, 5417 (1977). 2. Taft, R.W. and Koppel, I., in press. 3. This work.

~~V-- €~~

~~f-5.- CSDfiS-RQJUtXTXCN FFTJCFFfJiP El NUQ£7\R RHUKTICH lETECED FWR~~

P.Puiara, H.Acfceirom, H.Buttler, K.toerr, D.EXfcbers, H.Grupp, P.Heitjans, C.Kieae, ELECTRON SPIN LATTICE RELAXATION VIA NUCLEAR TUNNELING HO DLL A.Koerblein, H.-J.Strwdawmi Physikalischea Institut der Universltaet Heidelberg, FOR TRAPPED RADICALS IN GLASSY MATRICES West Germany and ILL, Grenoble, France H. K. 6UMWN, L. KEVAH and J. HtCHALIK. Department of Chemistry, Ua/nt U Cross-processes of neutron activated polarized nuclei (I) with surrounding stable University, Octroit, Hichlgan 48202 USA host nuclei tS) in diverse solids are studied using an in-beam WIR technique, A new electron spin lattice relaxation mechanism for molecular rad where the polarized nuclei are produced fay capture of polarized thermal neutrons. In glassy matrices has been developed based on modulation of the doc Te . The polarization is determined by measuring the o°-18O' asynratry of thef-decay dipolar Interaction between a trapped radical and nearby magnetic nucU radiation of these nuclei* the motion of ctinneling nuclei or groups of nuclei In the .disordered .7 i The polarization P was measured as a function of the external magnetic field B. ln'the absence of g-anlsotropy," which Is the typical case for free radic Cross-processes occur at those values of 9 where energy-conserving flip-flops It appears that modulation by tunneling modes Is more effective than norf between spins I and S are allowed, yielding reaonance-iike dips in the measured by lattice phonons in glassy systems for electron spin lattice relaxatio curves P(B). . -~ - - - ~ - lower temperatures, "typically below ^100 K. The quantitative {..aenjfian The following cases were studied: that the spin lattice relaxation rate Is linearly proportional to the :e a) Cress-relaxation at low B fields due the overlap of dipolar line profiles ai\d that K W vmsttWe ta the, tsataaic can^asttian of 1 he glass. Satu of spins Z and S: recovery measurements oF T. of trapped electrons 'n aqueous and orfjjnic - %i-7i± cxoBS-zelaxaticn in 7L1 metal for B<2Q G. trapped hydrogen atoms In aqueous acidic glasses, trapped silver a10^ i - ^-^ cross-relaxation ill ^'xi ratal for B<1 Mi. matrices and methyl radicals In glassy organic matrices can be Interpret - Orientation A*T*n*w of \i-^Lt" cross-relaxation in ^^iE single crystals. In terms Of this new mechanism. It appears that tunneling relaxation n,d b) area-relaxation at high B fields uhen qivyfnjmlar, interactions are present: provide a guide to models far different geometrical configurations ^ml t i - Tenperaturs ttapfTrVnff* of e2qQ(93fto) In LiHiOg by measuring the shift of rigidity of such configurations around trapped radicals In disorrierei si the a£A-93Nb cross-relaxation dips-in the P(B) curve" between 300 and 800 K. There also appears to be a correlation between the spin lattice ri=ia au - An = 1,2,3 and 4 - dlpc in tha P{B) curve of 2£>F In HpF-j (1*0) due to rate and radical decay, specifically for the decay of methyl rodleai, >n 2QF level mixing and 2OF-19F crosa-ielaxation (see figure). glasses. - Thermal annealing of radiation induced po^nt defects in M3F2 by measuring the depth of the' "ira=4"-dip of 20F. Measurements a,b) were perfortoed without any radiofrequency irradiation. c) Influence of a strong radlofreguency field F^ («B) on the crnss-relaxatian of *LX in the laboratory frame with 7I1 in the rotating frane; in 7U netal.

~~Figure: ZD Polarization of F in I*FZ versus B (c-axisB&). The solid line is calculated using a reorientation formalism imolving a two-particle uamtltonian~~

~~Ht19p^20FJ ^^ describes the Zeeroan energies of both 19F and20F, the quadruDolar coupling of F(I=2) with the crystal fielcs ar.d the~~

~~C413 C4M W1R SPECTROSCOPY OF TUNNELLING IN SOLID Sill^ .TRA-FAST NUCLEAR RELAXATION AND EVIDENCE OF AN ORDER-DISORDER~~

G. JANSSEKS, P. VAH IIECKE*, t,ab«-fratorium vcorVaste Sto£-Fysika TRANSITION AT 9°K IH Cu3VS4 en flaqnetisme, Kacholieke Universiteit Leuven,Leuvon (Bciyiun) . ARRIBART and B. EAPOVAL, Laboratoire de Physique de la IISMatifire Condensee, Ecole Polytechnique, 91128 Calaiseau Cedex, France By means of a NMR field cycling exneriinnnt, a direct mcasu- remeit of tunnel splittings smaller than I ueV can be performed We report experimental results of nuclear spin-lattice re- In a very simple way. An Increase ot the relaxation rate of the laxation of Cu , Cu and V in the compound Cu3V54 which is a nuclear magnetization is observed at those fields where resonant mixed-ionic and electronic-conductor at room temperature /I/. At exchange of spin energy occurs between the nuclear Zeeman system 1,5'K, the measured T, are nt 10 sec. for V51 and A* 1 sec. for Cu and ;he tunnel system. 65 The experimental method is very straiqhtforward: first, the and Cu - These relaxation times are very anomalously short for a proton magnetization is saturated at the meacuri'ng magnetic field semiconductor at this temperature. Several anomalous properties (IT); the field is then brought adiabatically to a new value and of the nuclear relaxation &re also observed at law temperature^ as left there for a time smaller than T: (typically 1 minute). Sub- unusual isotopic dependence of T, for the copper nuclei, and ani- sequently the field is brought back to the original value, where sotxopy and anomalous magnetic field dependence of T, (V ) . We the amplitude of the partly relaxed proton magnetization is mea- explain these results by the existence of local motion of copper sured from the FID. This whole cycle is then repeated for other atoms which modulates the quadrupolar interactions experienced by values of the magnetic field- The [partly relaxed) magnetization all nuclei. This idea is supported by X-ray studies of the com- will show a peak at those fields where resonant exchange tafces pound at 3CO°K which shou that each copper atom occupies one of place. four equivalent off-centered positions located around the normal

This technique is applied to solid SlB4 below 25 K: the A<-T crystallographic site. The observation of a sharp irregularity in tunnel splitting of the ground libratlonal state is measured the variation of T^ (V51) against tempe-

to he 0.22 peV. Also a 0.033 peV splitting of the T-levels is rature at Tc = 9"K indicates an order- 6 detected, giving strong evidence for a crystal symmetry that can- disorder transition in the occupancy of not be higher than tetragonal. these off-centered positions (see Figu-

In combination with our T1Z vs. T measurements at different re) . Below Tct the nuclear relaxation frequencies, these splitting values allow for the calculation uf should be due to collective motion of the energy between ground and first excited librational levels. capper atoms by excitation of the orde-

Also the lifetime of the T-' ' *•: and the height of rotational red fundamental situation ; above T^r barriers are deduced. the relaxation could be due to individual hopping of the copper nuclei between the four equivalent off-centered positions.

1. ARRIBART, H., SAPOVAt,, B., GOROCHOV, 0. and LE HAGAKD, Solid State Commun./ to be published. * Bevoegdverklaacd navorser, Belgian Nationaal Fonds voor Ifeten- schappelijfc Onderfoek. C421 cm PROTON SPIN LATTICE RELAXATION IN DIP^-TCNQ PUR STUDY OF ELECTRON IG J. ALIZON, G. BERTHET. J.P. BLRNC, P. DURAND. J. GALLICE, CHAHI IK H u(TCL'M)2+}. .'• C. THIBAUD. r.aboratolre d*Electromque et Resonance Magnfitique T T, •Th»u..r^in»|M.^.T'^nn-fl.D-H-Pfldiitia.InatitiitB of ChesJ.- E.R.A. 9n, Universitfe de Clermont I.I - 63000 - FRANCE . col PhiQicc,*C£idecJi' of 3ciencea,Chorno»ioiav.i(j.» 142432»U3Mfl

The DIP4.-TCNQ salt (tetraphenyldipyranylidenv - tetra- 2he lonparature depondenco of paranacnetic shift a and cyanaquinodimethan) is a pseudo one-dinensional charge transfer £Ul line widtlia in 5 nCTfllfsjJg have been examined ia tfce compound, with a high conductivity f 40 ( Hem)" at anbient tem- to-tfcsatura ran,;*. !.«• - 7« K in the hiji BUbiutudc field perature ] . negatively charged molecules such as TCtlQ stacked 47,4 U U i-i-ovidud ^ yufcrvoaduGtin,, ooleauid.Tho o**-plo in linear chains as well as the positively charged ones such -in tli«* ioru oX a yreoaod as DIPS. . Every chain is naramannetie ; transitions are obser- pelieL ima 5^u ved at 200 K on the susceptibility and 240 K on the conducti- Bed 5l*« iu XuUfttli.Tho Hold 11 vity' . we report the temperature dependence of the spin lat- bouotienttity in the tice relaxation time T, of protons . It may be considered there oaople voXuns did not ex- aru three kinds of protons (4 protons on TCNQ, 4 protons on DIP C»«<1 0,05C imd rolativa and 20 protons on 9 ) . Experimentally the relaxation is expo- stability was of the order nential, only one relaxation time is of 10"^ in hour.Only one observed and we can write i resonance line of gauaaian form maa observed in the N/T __^_ inveatigatad temperature 0 10 20 30 40 50 60 70 80 ranEe.The temperature 4e- DIP -r Lf pendence of the resotiance and the number of protons of kind i . ' i"- " iine centre ohift( n) in By using partially deuterated com- relation to diamagnetic

pounds the contribution of every protons is shown in Pig. 1.The paxanagr.otic shift (is increased kind of protons may be measured or proportionally to the susceptibility down 8K and then it decrea- calculated - The figure shows the sed rapidly.The uise of the second moment is noticably greater temperature dependence of the rela- than the sum of the nuclear-nuclear and electron-nuclear dipolar I*-, xation rate for DIP and TCN0 protons interaction in that tenperatura range,where the paramagnetic 300 T(K) The T£ behaviours are quits differeni shift achieved aaxinun.ThiB fact points at the nonhonogeneity of the low temperature range . A tentative discussion will be gi- the isotropic part of hyperfine interaction .This behaviour may be n.and the results compared with those obtained formerly in interpreted in terms of the theory of Bulaevskii/1/ for the one- dimensional disordered antirerromagnetic chain.

~~1 l.L.H.BulaevBkii1R.B.LubovaIcii,I.F.Shchogolev.' Zh.ek9por. teor. Fiz.",Pisiua(1S7a),j6,p.42. ,ry, 563, 197G~~

~~CH23~~

~~t.S.R. and spin lattice relaxation in (CH3)4N MnClj (TMHC) b, O.B0U»DEL. F.RUIZ, C.ABURT. L.H.E.Q. Univ.Paul Sabatier TOULOUSE (FRANCE) and S.CLEMENT I.E.F. ORSAY (FRANCE)~~

The E.S.R. spectra of a TWC single crystal has been studied at 9 GHz with temperature ranging from 4.2 to 300 K. The spin lattice relaxation tine has been measured by the modulation method which uses an amplitude nodulated ni- crnwave field and a detection of (diydt) (1). At 300 K we have observed the usual anisotropic line-width witn the (2) 3 cas3e - 1 dependence. Uhen temperature is lowered, the anisotropy decreases and vanishes below 40 K. For all the orientations, the line-width In- creases when temperature decreases. The effect is weak for 300 K > T > 100 K. It becomes more Important below 100 K with a strong anomaly at about 30 K. Two very different spin lattice relaxation times Tf and T; hive been pointed out by the modulation method (TJ » TJ ). T{ exibits the teaperature dependence T;"'. T'"1 between 90 and 210 K for a • 55'. Kith the sane orienu- tlon T; shows a more complex temperature dependence. On the range 300-100 IC it decreases slowly with temperature. Then it Increases quickly when temperature is lowered below 100 K. Furthermore at 300 K.T? is anisotropic by a factor 10 In the same sense as the line-width. Two kinds of paramagnetic centers seem to be present In the sample. (1)Bn" localized in the linear chains in accordance with the Id character of the material, (ii) Mn" with behaviour of a 3d system. This one could be due I: to crystal defects or trapping impurities. Evidence of two kinds of Hn" in TfffC has been already reported in other experiments (3). The anisotropy of line-width and the shsrt anisotropic T" should be produced by the first type of Hn3+. The line broadening at low temperature should result In the beginning of the short range order. A rough estimation for the concentrations of the two types of manganese gi- ™5: Cone. Hn"(I) / Cone. Hn'*.(2) . 500 (1) J.PESCIA Ann. Phys. W 389 (1965) (2) S.CLEHENT and r.TCHAO C.R.Ac.Sci. Z»2 16b (1976) (3) J.mCflRmO, J.TCHENDLER aid J.P.BENARD (to be published in Solid Ltatc Communications)

D1101 DW02 A amui or conriOTjMiiojs or croiic cowomns IHH low FOURIER THAHSPOHH IN VKSTIGATIORS OP C-13 LABELLED C1302 A1 nn: txiarr SHIFT IN LIIJIID uni AWUiln Ai.mvs OR THS MIGHT SHUT TBEOHI S.A.VOROHTSOV, D.G.DOLGOPOLOY and I.V.SVBCHtlBM, PhyiJeo- C. VAN DEB :iAHEL. W. IIIMRAWS and (t.^ffiTntJl IJHTT. Technlcal Institute of low Temperatures of the Ukrainian Solid State Physics Ijihontary, Ibtcrinls Science Academy of Sciences. Kharkov JI0I64, USSR Center, University of Crwiini'.cn, Croniniyn, Tlie Ne- therlands. Interest In the Knight *hlf t Investigation it connected with the KKR availlsbility of getting additional information afesut the Knight shifts of Li7 and In were determined, usin» a V'ari.in UiUc Line energy spectrua of conduction eleatrona. Generally the Knight KIR spectrometer, supplied with an aircookxl Jcwnr to reach tlie necessary liif>h ahlft is isotroplc and uau»llj 1* considered to be a reault of temperatures. The octal was dispersed in l.iP nowdcr, whkli moreover suniltcd averaging only the hrperflne contact interaction energy /!/• the reference Li resonance. „ K«-fr-¥X. , ,,-^.pv In liquid LiCd we observed the Li resonance throughout the whole concen- 1 tration raitfe, and found a behaviour of the Knight shift as riven in figure t •here %,is the Fauli apln susceptibility and \|Tj(0)| / la the F Any temperature dependence has not been observed. To Ret more insight in the density of the wave function of conduction electron* at the nu- origin of th? behaviour around 501 Gl, we have measured tlic- electrical resis- clear site averaged over the Feral aurfaee. tivity as a function of tevierature and concentration. A swooth Notdhc-lm like In thla aork ae preaent a theory of the Knight shift coming pirabola for ?(c) was found, which could nicely he explained within thi> Fabcr- froa a group of atatea in the region around a syaaetrleal point Zinan diffraction model. If of the Brillonln tone. The theorj allow to take into account the •agnetiaatlon froa each atate riH (n labelling the band) correctly. The Liln system has bK-n investigated in the sane way; in figure 2 the When considering; the Knight ahlft near the Foxats abere the Feral Knight shirt of the Li nucleus is drawn. Moreover we looked at the In re- surface changsa ita topology as aeeunr thbt contributions froa sonance as a function of concentration and found values for the Knight iihift other atatea fora a background which, in fact, la almost indepen— as given in fig. 3. Resistivity measurements have been started some time ara, dant of an.lnpurity concentration or temperature. Green functions and ma;' give more information about the behaviour around the coronosirioti Lt^ln are employed to obtain a feraula ahich allows to calculate direct- in thfi liquid. Preparing the san^les MC dhscrved that during the mixing of ly the value &H/H whereaa Sp expansion of the Raailtonian aatrix liquid In and Li, a noticeably large amount of heat is evolved. with coaplete account of the interaction between the electron magnetic aoaent and the nuclear spin ia uaed to describe the energy band structure fragment. The total Knight shift can be written aa

~~» aim of the spin and orbital teraa Ks and ((„),• A dealing with the~~

~~two-band aodel aa an exaaple (the corresponding pointa of bcet fee and hep structures under conalderation) exhibits the presence in~~

~~Ksthe ters which la linear In Fourier eoaponent of the lattice «~~

~~1. Sllcbter C.P. Principles of Magnetic Resonance, Harper and Row Publishers, Inc., Hew Tork, I9S3- 2. Ufshitz I.K. Zh. Eksp. Teor. Fi*. 38, I5S9 (I960).~~

C4304 USNEIIC iSD HBBOHiBCK ISOESRIIXS OF NMR STUDY OF INTERHETALLIC COMPOUNDS LUX TRiBSIEIOH KBtili CQUPOQHSS iBD iXXCIS ~> B. PERRIN. P. DESCOUTS and A.OOPANLOUP T.P.nHMTlHIiM.Institute of Badiopnysics and Electronics of the Iranian Academy of SciODCoa.Aahtarak J7841O.DSSR 0€partenent de Physique de la Hatiere Condensfier university de Geneve, 1211 Geneve 4 (Switzerland) In order to study the electronic structure and reveal the role of various electrons in process of production of hyperfine fields on nuclea^measurements nave been made of composition and temperature dependence of magnetic susceptibility and HHR As a part of the electronic structure study of intexmetallic (Knight shift X) on nucleai of transition metals cohalt,niobiuB compounds SB with CaCl structure, {1} and {2},(A •= Sc, X, La, and vanadium Cor some intermetallic compounds and binary alloys Lu and B « Cu, A3, Au, Pd, oh, Ir, Ru), we present the results of 3d,4d,5A metals.Hagnetic properties of investigated interme- we have obtained by means a£ NHR techniques for the system Lux, tallic compounds are well explained by means of rigid-band model. X = Cu, A9, Au, Pel, Rh, Ir. For example, the weaker temperature dependence of X in CoX-type compounds(X-£at!!bf7,Ii)with respect to one for the same metals We have measured the Knight shift at Lu- and X-site, and the spin- compounds,taken in 2:1 ratio tells about the presence of leBS lattice relaxation time T. at Lu-site, between rooni and helium nuater of unoccupied states ia 3d band for former.?he fillament

of 3i band of Co by valent electrons of Zr in CoZr2 and CoZr3 orplsinea the temperature independent paramagnetism of latter We analyse our data in connection with a two band model, previous- • ^fiunds.Since in the Hb-Ta and Iar-T alloy systems the density ly reported for (Sc, Y)B {l}and {2} and we test the previous if states >(B)nonotonously varies with composition,decreasing daasification into three groups, following the origin of d-spin from V and »b to Ta and similar dependence on composition is ob- susceptibility, with the new Investigated compounds Lux. served tarX and E,lt is asaumed,tbat the behavior of magnetic susceptibility and BID) in these systems is due to change of H(K). However the simple rigid-band model is not valid for Bb-V system, where correlation between S(B),K andjC is atsent.lt is assumed, {1} D. Seipler, B. Bremisker, D. Goebel, H. Happel, H.E. Hoenig that the constant of atomic hyperfine orbital interaction depends and B. Perrin, J. Phys. F, 7, 599 (1977) on composition,since in this system H(E) increases almost linearly from lib to T.vhile the nuclear spin-lattice relaxation rate {2} B. perrin, P. Descouts, A. Dupanloup, D. Seipler, to be J/ it£t} on the nucleai of V decreases.The obtained estimates of published ccr.t-acc.cor* polarisation and orbital contributions into E andJC with simultaneous account of s-d hybridization and electron-phonon ir.r traction reveal that Kmt andjCetX are dominant.The sb- Q-n-e it magnetic ordering in the investigated compounds and ailcy« under the presence of orbital magnetism is qualitatively oxplnined en the basis of band model,while the main role in the 7-rocess of hyperfine fields production on nucleai plays the orbital motion of d-electrons.

04406 D1105 PMJT01. CARBON AND CADHIUN MR BEMUREHtllTS «ND RELAtrvilSTIC CALCULATION OF HtUHTlfATITS SSTUUIIOB 07 THE GBdHll IMTSHAOEICK IN C4305 C4306 KAGK2TIC FROrKRTIES OP T.'E A 15 COHTOn.DS OP EVIDENCE PROM MAGNETIC RESONANCE OF LOCAL DISTORTION AROUND A

TRABSITIO!! KEIAL5 WITH HIGH Tfi PARAMAGNETIC IMPURITY D.H-KODESS, INSTITUTE ofKUCLEAR i'HVSICS, MOSCOW J.H. BAKER CUronricn Laboratory, parks Road, Uxt'ord, U.K. STATE UHIVSHSITY. , KOECOfl 117234, USSR The question of th* connection between the temperature of Previously used methods of finding the displacertent of ligana structural transformation, Tn, temperature of the transition ians in a sol in when a pai-amagnetic ton replaces a diamagnetic to the superconductivity Btate aztd magnetic characteristics ion, of difrerer.t size and [jossibly also of different valency, of tho A IS intensetallic compounds in diBcuooed. The nuclear are oscn to crixiuisjs. Several methods have bean used /1,2/ to mo3netic reaonar.co of r\ gamma resonance of Pe,57p',. paramagnetic susceptibility and integral intenaltiea of diffractional deduce the Ligand positions in alkaline earth fluorides contain- lines in a binary and ternary alloys is investigated in the ing rare earth ions. Deductions Ercra the effect of hydrostatic

temperature range 4-3Qfik with one the same high TQ sample. stress upon b /I/ are made doubtful by unknown local bulk Mn-HTffim of the temperature dependence susceptibility, typi- conpreEsibilities. Deductions from transferred hyperfine cal for transformation to the antiferromasnetic state ±a interactions (r_hfi) /2/ require assumptions about the dependence obtained at the temperature Tn«, The abnormal change in the of covalent contributions A and A upon the ligai\d distance R. anisotropic Knight shirt [i~Jand gannia-resonance line broadenine For ions beyond Ui« itgsnd bJiell of a rire earth -on the inter- have been discovered as *he temperature descreaaed. Anieotropy action is purely dipolar, so thfi do give Information' about at tho magnetic properties io also max!nun at Tm. The value

~~of tha temperature coefficient!! dKiBO/ dT, *&„£.,„/ dT, d\/ ionic displacements, but the accuracy is limited. From dis-~~

dl displays clear correlation with the value TQ and with the placements of the more distant shells &ne can make some anomalous change in the Integral diffract!onol reflection deductions about ligand displacements. Further, one can make ( degree of instability and strong anharmonicity of atoa vi- a detailed analysis of the variation of thri with host crystal, bration in. the crystal lattice ). This agree with the results without making the assumptions made previously. Using all of of the investigation of forbidden reflection intensity [2]and the available evidence one can construct a self-consistent the valent electron distribution at room and low temperatures + + for single crystals of V.jSi, V^Ge, HbjSn. The proposed phe- explanation of the thfi of Gd and Eu in alkaline earth nomenological model, in which the most probable sourae of the fluorides, which involves a determination of the ligand distances. abnormal behaviour of the A 15 compound involves a relatively high density of electrons near the Fermi energy in these ma- 1. Hurren W.R. , Nelson H.M., Larson E.G. and Gardner, Phys. terials and possibility of original of the magnetically Rev. 185, 624 (1369); Edgar A. and Newman D.J., J. Phys. ordered state at the structural transformation temperature. Cj Solid State phys. £, 4023 (1975). 1. Tratjatov B.H.. Kodess B.H. a.a.Izv.vuz.Fislca 5. 141. 2. Babaerschke K., Z. Physik 252, 65 (1972); Anderson C.H. , (1977); Zh.Bxper.Teor.Fiaica 65, 4, 1551, (1973) Call P., Stott J.P. and Hay**. W. Phys. Rev. BlU 3305 (1975J. 2. Kodess B.H*, Butman L.A., Forai-Koohitz K.A. Docl. Acad. Hauk SSSR 238, ( 1976).

~~C4307 C430S~~

THS 2EB0EY. 0? SKH IS StrEEBCOHOTCTOKS WITH THE PARA- SHK AHD HB1AIATI0H IB V^.jBbj.Hf, V2 Hb Zr COHFOUUD3 HA5HBTIC IKHJBITIitS M A SIEGIBT SIAl'E T.I.KOZHAHOY, A.P.STEPAHOV, E.P.R0UAS07 A.A.KOSQY and S.L.T5ARE7SKII. Caznn State aniverolty, titute of Metall Fhyaica Academy of Sciences of USSR Kazan 420008, USSR Sverdlovsk, 620219, USSR

The observation of the magnetic rasosance in normal con - Tbe iaotropic and anlaotroplo EQZ Knight ahlfte, the quadru- ductars on nuclei of paramagnetic ions in a singlet state allows pole coupling conatant, the apla-lattice relaxation time were to determine parameters of the crystal field and of tha conduc- studied In paeudobinaiy conpounda V Hb^HI, Tg Hb Zr (x,jrcO,3) tion band /IA in the teaperature range 20 - 300 E. The intannetallic cofflpoonda la this paper it is ahowzi. that the conditions on tha mag- ZrT taT 01 Hf T2 z ' 5 atructure (the cubic lavas phase). In the natic resonance oa tha nuclei of the paramagnetic Van-Vlaek's temperature range 100 - 120 E the structural transformation is ions in superconductors at impurity concentrations-^ 0f 2 - 0,3 obserred in thRBe compounds* Ite depth and position (T ) depend about tha sanef as those in ictermetallic compounds, for example* on niobium concentration. The temperature dependence of the Pr-pnictides and Sr-chalcosenidea in normal state. Usin^ ths ef- electrical reaistlvlt? and magnetic susceptibility shows that foctive Hamiltonian of electron-nuclei interactions, constructed the electronic structure near the fermi level is changed at T~T . in /?/, formulas for g-»factor shifts of the effective nuclear As result of discussion of the experimental data on the meseat JU. « of Van-7leclc*a ions and of the nuclei of diacsagnatic Knight shift, magnetic susceptibility, spin-lattice relaxation atoms bare bean obtained, having Into consideration the influen- time and electric gradient at V51 nuclei we hare eatlmatad the ce of the crystal field and exchange Interaction of impurity ions one-electron density of d-atatea at the Tenei l«Tel and tha with the conduction electrons of the superconductors* relation between densities of o-atatas with different type of A formula for the time of tna longitudinal relaxation I of the angle aymatry. /£ l£ in tha superconductors caused by the exchange interaction a In approaching thd teaperature 1 to I, n observed o conside- of ion's magnetic moments with the conduction electrons (s-f rable increase of K^ dus to inlaotropy of the distribution of exchange) has been obtained. T Is shown e a sent i only to depend on electronic states at the Vend, lexel. it should be noted that the parsaeters of the crystal field in which ions are disposed and on smearing of the n.m.r. satellite lines which we have recorded is the magnitude of the s-f exchange* The influence of fluctuating due to the temperature dependant distribution of electric gra- coupling of band electrons In X-15- type superconductors on the dient at V51 nuclei. These effects are the moat pronounced for relaxation of/C /3/ is being discussed. tIf V, jlbg jHf. The replacement of V by ib leads tc a reduction of X. S.A.al'tBOhuler. froc. 16th Congress AMPERE Bucharest, the anleotrspy of electronic states for *>*„• 1-5 Sept. I9T0, p.I. Irom the analysis of electric field gradient q was found 2. S.X*XBar*VBfc±i. Tiz. frrerd* Tela. 12, 67, 976 (I97X). that tha decrease of tha electric charge transfer So T atom la abaerred in compounds 8 3 3 2244 3. 1.A.E060T, S.L.Tsarerskii. Plz. ftrerd. Tela, 20,^3, pus Srz(qrf),e1Os»)*s»"* ),, HfT2(4-O,B2(4O,B4 1OO~ 3 3 2 3 V5 (1978) am" ), TaV2(o-2,38 10" *am" ). thin giTsn riss to a increutof lattice cantribution to the observed rslue of eleotrio field gradient .

D4409 D4410 Deteroinatio C43M C4310 NMR METHOD 04 THE OWN FIELD FOR REGISTERING RADIATION EPR STUDIES OP ELECTRON PROPERTIES AND INDIRECT EZCHAHGB EFFECTS IN FERROMAGNETIC MATERIALS UITSHICTION IN THB FdCdH SYSTEM DbAKSENOV. SH.IBRAG1MQV, V.BfK, S.PIVCVARPV. USM1KOVA and I.A.GAHITOT.T.TT:. N.U.SULEYMANOV, Physico-Technical Institute O.3TAHOV. Institute oj Nuclear Physics ot the Academy of Sciences of the Academy of Sciencea of the USSR, Kazan 4?OO23, USSR o( KozSSR, Alma-Ata, 480062, USSR. H.DRUUS, Institute for Low Temperature and Structure Research of the Polish Academy of Sciences, Wroclaw 50-950, FRL NMR method in the own field has definite advantages in the study of Electron paramagnetic resonance in the PdGdH syatem is stu- if" radiation etfncts In solids as it simplifies the problem of securing radiation died in a wide interval of hydrogen concentrations over the tem- protection. The report gives the description at the radiospectrameter with perature range i«fi to 30 K. Two well-Baparated EPR aignala of remote control placed in a hot cell, with the frequences range of 120-250 f * "•'•' the M3+ iona corresponding to the d - and ^-phaaes of a pal- Mhz and the results of experiments. Pure metal cobalt has been used as ladium-hydrogen eyatem were observed in a mixed phase region* an object of investigation. Samples with different content of lace-centered From a hydrogen concentration dependence of the EPR signal amp- cubic (FCC) and hexagonal (HCP) phases have been irradiated at dif- litude! the phase diagram boundaries were estimated* ferent temperatures on the isochronous cyclotron by protons 30 Mev and In the p-phase of the palladium hydride, the dynamics of o£ - particles 50 Mov, by A -particles Z Mev on electronic accelerator » coupled local moment - conduction electron spin' systems is in- a» well oa in the active zone of the WWR-K atomic reactor. It has been vestigated, and the existence of the electron bottleneck is found that when sonnies containing mainly FCC phase were Irradiated, the line at the frequency oC 213 Miz.practically was not changed, but in the analysed* samples having HCP phase a significant change o| this Itne was noticed There is observed a strong BPR line broadening due to the even at comparatively small doses. In the lost case the 221 Mhz line was magnetic ordering of the Gd ions at temperatures below 4.2 K. also slightly deformed. Such character of changes of the lines may be due in the fi -phase* This broadening is known to arise from the liu- to tie phase transformations, while the radiation defects inlroduced under dernan-Kittel-Kasuya-Iosida (RKKI) nxchanga interactions* The l-i: the given conditions of radiation evidently da not prevent (he movement main feature of the results obtained is the observation of on of domain walls. exponential character of the magnetic ordering temperature on the hydrogen content in a sample* Measurements of electrical Experiments hove also shown that the plastic defamation leads to a resistivity showed that the mean free path of conduction elect- significant change of (he signal and the subsequent irradiation causes ra- rons correlates with the hydrogen concentration- The result ob- diation annealing. * ' tained clearly demonstrates that the mean free path effect on The results show the possibility of using the described method tar in- the RKKI interaction is in good agreement with the theoretical vestigation of the radiation stimitaled phase transformations as well as predictions made by de Gennes [.]. other radiation effects in ferromagnetic materials.

~~1. De Gennes, P*G. J.Phye.Radium. 23, 630 (1962).~~

can C4312 HREUCTIOH DYHAECS 0? sra SYSTEMS HTH DICTEHHIT H2S0HAHT SOUND ATTEHUAIIOH IH DUKTX II-TY.PE SUPERCONDUCTOR. g-PACTOHS B.P.V0DOPIAM0T, V.A.ZHIKHAEKV T.3.AH3HU2ZB, B;F«KflKOTCTSKII end M.H.ZARIFOV, Phyaico-Tech- Physical-Technical Institute of the Academy of Sciences USSR, nical Institute of th* Academy of Sciences of the USSB, Kazan 420029, USSR Kazan 420029, USSR , The reaonant contribution in sound attenuation coefficient It is known that the electron bottleneck effect (KM) can A^re^due to aound absorption by nuclear spins is considered for be observed In two coupled spin systems with equal g-factors II-type superconductor. Zn the normal metal this contribution (g of conduction electronsxg of localized spins}. In thia re- nol^j may be calculated from the eystem of elastic theory and port we present the results of an experimental and theoretical Maxwell equations /I/. In the local limit 1%j,..- the electron plasma fre- ty of tha erbium ions (go>*6'78t g-^2.033) are studied by the quency, x -the electron mean frue tijae) one has: SPR method C 4-1010Hl, T-1.7-12 K). There was observed a, characteristic dependence of d&H/dT on the concentration* Introduction of the non-magnetic impirririos (Si, Ag, Au) ta- HereiZ -the cyclotron frequency of ions, b".- the metal conduc- ken as spin acatterera for conduction electrons, and the inc- c tivity, /("•) • f'(al) + Lf'(tu) - the dynamical nuclear magnetic sus- rease of the lattice defects by a sample deformation led to a ceptibility. slope increase, i.e. to the breaking of BBH. Experimental re- Xn durty XI-type auperconductor (in thia case the above men-1 sulta obtained are described as solutions of a boundary value tioned limita are valid) the correction to (1) quadratic in the problem for a case of different g-faetora. The calculations pre- order parameter appears. This corrections are negligible near sunted give a proper explanation of the 2PR line shape distor- the critical temperature T , but tion. e rtorniat the magnetic field inhomogeneity :ta( In Borne heavily doped samples the precipitation of the se- (the vortex structure) must be ta- cond phase, approximately corresponding to a compound SrCu^ _/*\ ken into account.Thus &d-n& ia ob- atoichiometry was observed. This compound experiences a magne- tained by averaging of (1) on the tic transition at T-7 E (it was shown directly by the BIB method sunTcmdiictor.. . magnetic field distribution(see, and by the measurements of electrical resistivity), this com- 1 for 0X./2/) The computer calcula- pound strongly influences tha electron properties of tha KriCu tlon was made for triangular vortex solution resulting in a sharp change of the lineaidth slope lattice and the results are repre-

dan/iT* The behavior observed can be explained by the influence sented on figure ( x « ^r5n • >«V» of strong spin seattering-of conduction electrons on the preci- »!,<•>£ -the minimum field in metal. pitations which lead to the breaking of the electron bottleneck. magnetic fields in core of the vortex and in the saddle-point, respectively). IM J.J.Qulnn. J.Thys.Chem.Sollda, 31,1701,1970; V.Ya.Kravchen- ko. Zh.eksp.teor.IlE. ,5&, 1494> 19t>8. 121 I.B.Aleicoeeveky at al. Zh.eksp.teor.Ha. ,22» '•523, 1977.

D1113 D4414 SBXBaTuV. - 77 DE DPBCIH03C01T. SOB ASPECTS SHfTTUPIBIOAL QUIHTOI-CHKIIIOIL KDDO CALCT3LATI0B 07 C1313 1T1 COHDU3TI0H S1K0IROH SFIH KOHO IK SMALL METALUC JARTIC1BS n in'iwii oRTBOBBonio moon* vmtmat IH HEOTROH-IBRADIATBB 11? ORVSTA1S O.J.tOOAI. ut B.STAmail, Instituta tor In taaptntan y.G.CHKRKASOY. B.G.K11ARAKHASH'XAH, 5C.I.TALAHOT, ShyBlcsi-Techni- ul Struotura Raaaaxah Poliah Aaadaaf of Salanaaa, caX Inatltute of the Academy of Sciences, Kazan 420029, USSR 50-950 K.K.5K7ARK, A.'fo.VI'rolS, Institute of Physico of tha Latvian Acudoicy at ScienceB, Riga 226021, USSR Tha auolaar aaanaUe rasooaao* of ' Yb ud H km The rooulta of an e^porimontal Dtudy of conduction electron been studied at room teaparature and at 77 K In ortborhoablo spin ocho and the EPH In Id? crystals, containing small lithium jtterblu. dlnjdride.abreover.the aaguatio ausoeptlbilltj baa particleB.aro praaentad. All the raeaoureKents wars performed in been •aaanrad In tha taaparatara range 4.2-294 X.Ialght ahifta the X-fcond over the teoper«ture range 77 to 450 K on tha crys- and o« jbeorption llnewldtha ara raparted.Xaa jtterbllai Blight tals n-irradlatod with a done of 6*lO1B-i- 2«1019n cm2 ot T-450 K shift or +0.375 • 0.025* baa bam found. Iha raeults iadiomta (the Ll-I oanplea) and on those thermally annealed nt T»1O5O K th»t jtterblu. iona ara divalent in tha studied hydride.This after irradiation - to have the particles nizes increaaad CI4-II ooaolualon la alao aupporiad bj ooaparlaan of axparlaantal She li-I Bnaploa ravoal intense EPS signals with the linewidtna proton aaoond sonant Talna alth aaloulatad aKafahloh asp riaoatt from 0-5 to 2 G depending on the irradiation conditions. On the- to ba alMaat antlrrij dna ta tha H-H dlpola-dlpala Intaiaatiaa. ao very saoploo ths electron spin echo aigtialn ware diBcovarad, Tha analjais of 1T1Ib Knight.ahlft and aacaaUo auaoaptlbllltj and the oocillationu of an acho amplitude with the tine interval data lndieataa that tha orbital taim has aa]or eontrlbutioa ta T between Che pulses (the oo-callQd modulation affects) were tha lattar.fha uaaurad protaa laight aktft kaa baaa found to observed. »s uolieva it to bo the evidence for the existence of ba iar* vitoln axpariaantal trror iO.OO3*.Th« national narrm- iluMKOgenoouu lino broadening caused by hyperfina interactiona. ing or tha protoa lintnidth ma not obaarvad ainoa tha llna- In li-II oamplea extremely narrow EPR lines isith the width «ldth at 29* K dlftara oalj alightlj fro. that at 77 K, ~60-60 EO were observed. Modulation effects were Bbaant in spin acho while the echo decay law waa non-exponential. 5fhis particular character of tha echo decay io cauaad by the surface relaxation maehaniami its1 extreme Benaitivity to the law of particles distribution versus diameter enabled to carry out a detailed Btudy of thia distribution. Using a re-constructed distribution wo have succeeded to describe the whole complex of the properties observeds the decay law and echo aiRnal dependence on the powe? of pulses, the SSR line shape: to determine a sur- foce opin-flij probability, the tine of Intrinsic electron re- it laxttion &ai its1 temperature dependence; to divide the contributions of homogeneous and inhanogeneouB mechanisms to the SSR Unswidth.

C4515 C4316 FARAliACHETIG BBLAZA7I0D OP COBDUCTIVITY EI£CTR0H3 DUE TO A COMPARISON OF SQUID NMR AND NOISE THERMOMETERS INDIRECT IHTERACTXOH VIA A PKOHOH ?IEU) II. AHCILA, G.J. EHNHOLM, S.T. ISLAMDER, and B. RANTALA, B.A-TIil£3KAEV, B.K.QHABI3ULLIII. Kazan Fnysical-Technicol Law Temperature Laboratory, Helsinki University of Technology, Institute of the Academy Science USSR, Kazan 420029, USSR SF-02150 Espoo 15, Finland

It*s knoim that the indirect exaange electron interaction Ke. have constructed two primary thermometers which employ SQUID via a phonon field is the Buacrconducting state appearence- The magnet one ters developed earlier by us /I/. The SQUID NHH thermometer above interaction givca the poeaibility to determine the rela- has been used to measure the spin-lattice relaxation time T. in latioci tine of transport at t ^.10 K- One can 3uppaoe that the 119Sn powder of 99.999% purity and of 30 jjta particle size. Simulta- indirect oloctron-eloctron. interaction via a phonan field with neously, the thermal noise voltage generated in a resistor was meas- Dpm reveraal IB the nain nachanicn in the conduction electron ured using SQUID techniques to obtain an independent determination poroisagrtGtic raloacstian at low temperatures. o£ the temperature. Measurements of the steady field magnetic sus- We calculated the conduction electron paramagnetic relaxa- ceptibility of nuclear paramagnets. such ae Cu or Pt, are very sensi- tion tines !?, due to the indirect electron-electron interaction tive to electronic impurities j a 1 ppm concentration of magnetic via a phonon field. In the oase under consideration the part of ions will give rise to a susceptibility comparable with the nuclear . tha indirect Interaction works in. th« relaxation proseests xnat contribution. Resonant methods for measuring the nuclear susceptibil- leads to thfl spin state change of the interacting electrons. T.. ity and T.J discard the impurity signal and pulsed NMR on Pt powder is deteralned by the imaginary part of self-energy operator of has become a basic thermometer in the Green function the mllUkelvin region. The spin- spin relaxation time of 119Sn, however, is far too short for this tech- m CD nique. In SQUID NMR one first de- stroys the magnetism of the specimen vhera P - is th« Tortoi part the indirect interaction. It waa by resonant RF excitation and then, xeceiTed that the expraaion for 1^ in tha aeniconductora A^Bj after having shifted tha frequency and in mstals at low traperatuxsa will ba in the following form of the constant amplitude RF signal off resonance* detects the spin- lattice relaxation using a SQUID mag- netowstet. This provides a convenient whare AfB ara- eana^tonta the Alecftron-phonon Intaraction with apln nrenal in matals and aomiconductora, e - alacttsn-phonon method for a continuous sampling of intaraction constant, S - sound velocity, p - tha oriatal den- Tj 72/, The sensors of both thermometers have bean-installed In the Miti, Pm - tha 1*TKJ ware vector* mixing chamber of a dilution refrigerator. The measured T vs. Tj is The comparison tha axpraason (2) with tha axpariaantal data displayed in the figure. The construction of the two devices, the ex- *-,(!) for Xa ( lahar and Saep, 1955), Al ( Sables, Shars-Dsat perimental technique, and the results will be discussed. and etc. ,1977), Inab ( Iaaacaon, 1969) glvaa good qualitative 1* Ahola, a.*' Ehnholm, G.J., Islander, S.T., Ostman, P., and Ren- agreement. Thus bna can obsarve at low.taaparatiireB tha lndlxaot tals, B., to be published. - alactron-alactron Interaction part with tha apln reveraal via • 2. Moberly, L.A. and Symko, O.G., IEEE Trans. Hagn, 13. 35S (1977). phsnoa field in tha relaxation proseas of conduction electrons.

~~DM17 04418 i C1317 MS astaltank at tr rnisj- dop*d HI? L,Iuwnk*,S.Iau>pka, •.nafollaika, l.Sl.rla •Hill 40-0C7 Bktmiu. KOnd.~~

It bu tnn r*port«dI11«wt n> of MMondaotion tlaotcon bottumok la brokn liy By Ktdltina, tnt ehufi of tM xtaanmt Htl4 i» nnru *• «u indlotad hy H»Mg»»» CaitlnorT la osataaJltT with othtr «ip«rl»«iit« [3]. »• km otiKm! it ltaur

dipmdaii of th* zulaUTltr tad *e w ebtelnad trim th» naiatlTltx mnmtti u * (uaetloa of B* ooaomttatica, «o«pt for nail Si aontnta. 9HM, tof»«JMT with ta >il»p«U«nQ« of tat BE KHunn tiaUa eaa Iw anrUattd to abtacM Is th* Mtlaa dlatribitlos. Bu X-nr etttlea dlttrloatioa wirainti Of BOBMl I»T»» ^BM«« B«T« MT«al«d B* lad Al O*UOU IB Sa'lBd 164 aitu, r»«p«atlT»ly. Oar I-r«r limitation of tut abar* •jritua aaggut th»t tM eatlm loaatla la partly nnrud, th* nnrilBUltr s*la« x-d«r«ul«nt. «kl* caa aeenat for th* ruauae* tlaid Inorw* *xo**dlBg ,th* bottluaek dionui.

~~1. Sum-Snag Igajna, t.B.Chlu, P.H.BlUton, A,H,8tnart and bSkfalarlK Ihjalsa 86-88B, 181 1977 2. H.Baugwa, Progr.unor. Sbjn. 21, 483 19S9 3. B.H.Ujrlor, Una. mj,. 24, «ai 1975 4'.'~~

D411 0412 OF THE POSSIBILITIES TOR THE JOBBFHSOtt B7PBCT SELECTIVE EXCITATIQH TICHMIQUES IN FOURIER TRANSFORM WR WPLXCATIOH IN KAOWriC BBSCMANCB BXPERIMSTS R. WJTABilJA, iwtltuta "Budier Boikovld", 41Q00 Bagreb, C.A.MORRIS lad R.FUUKAB, tfnivereity of Oxford, Fhyeical ChtmUtry Yugoslavia Laboratory, South ?uk* Roa4, Oxford, England.

The historical and technological development of the magnetic The icope cad power of Courier transform KKR nay be considerably resonance •uparintmts clearly indicates, the trend toward the higher enhanced by employing selective excitation aethodi. The use of selective frequencies. It la reasonable from the information theory require- pulse eeouence* allows selective excitation, inversion and saturation to ments, and the fundamental physical limitations consideration. From be perfozsed on conventional pulse Fourier transform spectrometers. A both criteria of resolution and sensitivity, the trend toward the sequence of a identical short pulses of flip ancle a « n/2 radians, spiced T magnetic resonance experiments at higher frequencies is imperative. accondi apart, will affect only tttose resonances which are offset froa the During the last years, TOW experiments at over 500 MHi are tranaaiecer frequency by Au a afx Hi, where n is an integer. If the effects reported by E. Wintering and J. Hesse (1976), and EPR experiments a£ relaxation «re neglected, the emulative flip angle at theie frequencies at 500 GHz corresponding to submillimeter wavelengths, have been vill be act ri4iane, while the selectivity o£ the irradiation will be of che reported by J. HagarinOj I. Laura en and others (1976). The lack order of I/Car) Hi. In the region of linear ipin response, the effects of of efficient radiation detectors and emitters at millimeter and auch pulse sequences may be predicted from the Fourier transform of the submillimater wavelengths is well-known fact. tranaaitter modulation pattern. A vide range of applications of theie The application of the, high sensitivity and good spectral frjqutncj selective methods ii possible, including the examination of partial properties of the radiation detectors, based an the AC Josephson apectra froat individual chemical eitef2*3, the meaaureaent of chemical effect, in magnetic resonance experiments, is discussed and proposed. exchange rates , ths aelective oeeiureraent of relaxation tiawe, and the The radiation spectrum of the Josephson DC effect is derived, far suppression of unwanted signals. the different junction and resonant cavity properties. The optimum operation of the experimental set up, contesting of the Josephson 1. Bodenhausen, G., Frvenan, R. and Morris, G.A. J.Hagn.Resonance t- effect based radiation emitter or detector within a' resonant 23, 171 (1976). cavity coupled to the second resonant cavity loaded with the 2. Freeman, R., Morris, G.A. and Robinson, M.J.T. J.Chem.docChea.Ooommn. resonant sample, is analysed. The pecularities, due to the use of 1976, 754. the extrenly high Q (superconducting) resonators, is investigated. 3. Horria. G.A. and Freeman, R. J.Magn.Kesonance, in press. Two additional reasons for relating the magnetic resonance and Josephaon effect experiments exist. As first, both phenomena may be regarded as macroscopic quantum phenomena, and because of the .exhibited spatial and temporal coherence, mutual interaction seems promising. As second, the formal analogy of fundamental relations for energy difference of quantum states in both phenomena is stimulating, to relate directly the experiments at the same frequency.

D113 OTISTIGAXIOI OF THS USOUK SMOSKCim THWSEBt HBBI M.I Mts AEDDOIESSBEPOKrCKINSTBIJMEMrM, DEVEUXWHIS FBEKMBI1. a SOLIDS L. R. DMam aid K. D. SCaniSEIN, state University of Hew York, SKny Brook, I.i.IBHOTi, V.S.MDBS1B, P.I.UbaaeY Hat Vort 11?« USft ar^ vaufertijt Chiversity M»ii~i School, Nashville, Physioal Inatltat. of «it DSSB loader of Soianete, Tsrniessee 37232 USR. and Bruker PhyriX R.G., D-75U Karlsruhe, ETC Ifonow 117924. BSSBV _1JI 1972, Byde and Dalton /I/ intzoduced the first of several dynamic . a rnmbar of physical paanowna bare ohanctarietic fraqiun- saturation transfer electron paraDBgnetic resonance (sr-£PR) exrerinents by et« lying ia a -!-"»-"» raglon. Ihay an. for axaapla, examining tm of the several Fourier conjenents of the spin response observed •oaa electronic tnnaltions la ionic cryatala, cyclotron reso- in the presence of an apiUflJ zeeman mnrtnT^™ field; they were able to observe rotational diffusion of nicroxide spin labels characterized by rotation- nance of fr« carrier* in aaalconductor., magnet onlaaaa reso- 7 3 nance, in alactron-hola drops in Oa-typa aeaioonductor* and al correlation tines in the previously inaccessible time region of 10~ tol0~ flald affects In aasdeondnctor filma. low taaparatoraa and «ag- sec. Sr-ffll has been appHprt to a muter of slow rotational notion problems, natie flsid are typical of theaa experiments, including the Euprajnolecular aggregation of the contractile proteins actin and lo aolra the abora mentioned problaaa w* hart dayalopad a non- myoain and of Hanoglobin s (sickle cell hanoglobin), the binding of spin- raaonant onaaloptleal tranaartaalon-tjpa sptetroaoopa opa rating labeled fatty acids to cholinergic receptor sites, the slow (collective) no- at 0.3 - 3«a mralangtiu and T7K and 1.5-4.at In aagnatlo tion of hydrocarbon chains in i4f ^jftnriii bilayers, iirWji jy^pM motion in fialda ertatad fj •laotroaapiat and aapareonducting aolanoid. gel phase lipid hilayers, the notion of HW and COW viral particles, the

i a 152 th» .jin-Uttic. nlp.ll. of .MM aran. in SHH EZPElLDfEKTS HH TITB RTTDEBm-n D421 D122 1J13, THB Qt SILICOB COOfiffiWUICB IDMSIR mOTTION 'H AND c NHR MEASUREMENTS OF OIHETHVLCHLOROFORHIMIMIUH CHLORIDE AND D1METHYLFORMAMDE HTPROCHLORIDE OR IBS RH8 TWIT 0* OBOIBOSIUCM 00HFD1BD8 J.PAA5IVIRTA. I.AHONEH and H.HXKLI, Department of Chemistry, S.H.UHDCRI, A University of JyvSskyll. Kylltkinkitu 1-3, SF 401OD JyvUky.U T.J.SIDORm and K.G.TOBOWDV, institute of Organic Chemistry i 10, Finland Siberian Division of the USSR Academy of SeianetD, Irkutsk 66«O33. USSB Dimethylchlorafarmiminlum chloride i. Arnold reagent /I/, Is successfully used in acylations /2/. e.g. in penicillin syntheses /3/. In Ilia main regularities of HUB parameters changes dua to silicon connection to our mechanistic studies on acylation we have measures coordination number extention to 5 have baan eatabliahed In tha at different temperatures the 'H and 13C NHS spectra of X and u« exaople of silatranes I^T(0CH^5H^JI /I/ and complexes of reaction product Z which proved to be Identical with the 1:1 adduct orgsnyltriacyloxysilanes! XBiCOCOIOji with, a number of organic of hydrogen chloride and dimethyl foraimide 3. The measured rotatio- beses /2/. nal energy barriers of J_ and 2 were greatly lowered compared to that Fsntacoordinate silicon coapounaa differ fron related tetra- of 3. The results are explained by the following scheme; oedral onas in gnatar values of ^51 acraaning constants, protons of tea substituant X and its 13C and 19F nuolai reacted V froa the silicon atom. In contrast, acraaning of the 'z and *F N=C^N=C C\~ =*= N—C-CI pi nuclei neigbouring to silicon is lower. The pentacooxdination of the silicon atom is accompanied 07 an incraaa in the absolute 1 29 values of spin-spin interaction constants, J( si^C) and + R-COOH +H2N-R CO-HN-R" - HCI 2J(a9Si1H5, and a decrease in 1JC29SinH) and 1J(29ai19»). The ' 1 - aependonee of the observed changes on tnermodynamic character- H istics of pentacoordinate silicon derivatives has been discussed. i=c cr >*s= A nodal explaining tna obtained results in terms of the hypothesis /3/ on hypervalent bondine of the pentacoordinate silicon atom in the axial fragment of trigonal bipyrasdd surrounding has beau proposed* • - •HCI T —^ H3°N 1. Festunovica T«A«, Tandura S«H« VoronkDT 1S«G,, Baryshok T*F«, ( H3C H H3C' Zelchan G.I., Qlttkhiklt V.I., Bigeloardt G., Bitsnowslcl u., 23 Spectroscopy Lett., 11, No 4 (1977). Thus the resonance hybrid structure 2&**3t> of dinethylfomwide 2. iarin U.S., Synojsis of Candidate Dissertation, Irkutsk, 1977. in which rotation around C-N axis needs a high excitation energy is absent in ^ or 2 and their 1$oners JJ) and 2b have single C-N bonds 3. SiiorlOn V.7., Poatunovich 7.A., Toronkov H.G., Sokl. U B63B, a Honing an easy rotation. 235. 1363 (1977). 1. Arnold.Z. Coll.Czech.Chen.Coanun. 24. 4048 (1959). 2. Zaoral.M. and Arnold,Z., Tetrahedron Letters ^4, 9 (I960). 3. Novak,L. and Ueichet.J., Brit.Pat. 1 008 170, IS.8.1963.

~~D423 S??5C? C? T-E SPDI-OHBITAL WTEBICTION OS THE HUCIBAB IUGS3IIC SHIELDIH& IK UOIBCUXSS SI.I.yOLOSICiEYl.. I.K.BKB4HE, Shysics Institute of the Leningrad State University, Leningrad 19890*, USSB~~

Both the electronic and the nuclear spin-orbital interactions influence tha nuclear naffoetic shielding (J* snd tha nucloax spin-rotation interaction C^ in ffloleculea. Ke evaluated the electron spin current contributions toff* and c" by the perturbation theory end the vector potential variation aethod. The IHDO electronic wave functions were used. Our results show that the electronic spin-orbital contributions to proton cngnetic shielding for the oolecules HV,~ BC1, HBr and HJ are 1 0" 3 = 0.21 ppn, 0.85 ppu, 4.46 ppa and 13.79 ppn respectively. Ihese values are raspectively 0.7 *, 2.6 %, 11.5 % and 30.3 % of the total proton oagaetic shielding. Vor tha sans molecules we found that the electron spin currant contributions T.a orocon spin-rotation interaction constant mi cj[ = 1.192kHz, 2.«* K£l, 10.235 kHz and 24.375 kH» or 1.6 %, 5.7 *, 23.8 * and t-i % of the ezperiaestal total vnluas of C8. It appears that even in closed-shell molecules tha electron spin current should be taken into account when experimental nuo- loar spin-rotation interaction constants are used to calculate the orbital paramagnetic shielding. Sic mo'iified mill equation was then used to evaluate the effect of the nuclear spin-orbital interaction on the values of g *• and cA. It was shown that the relativistic correction to zhs reiatio.i between the p&ranagnetlc shielding and the nuelaar ^pin-rotetion interaction is given exclusively by tha Thomaa precession tera. I7ith this correction we obtained a more exact value of the proton magnetic shielding constant in B, at the H oquilibriua internuciear distane* 0" (Be) . (26.659 + 6.00*) ppn. This value nay be usad to establish more accurately tne absolute PJS chemical shifts scale.

A5U A 512 UHUSUAL W« PHEMQHEK* IN CFC«2-CfCt2' THE STATE 07 WATS) ADSORBED IS SMAIL P0RI3 0? HICHOSCOPIC HAHOID T. STOCS ind DAVID C. AILION. D«»rt.«,r .f ok«.i_. ..A D45Q1 ' 01502 BOBMILUHETOE HAOIBIIC R3BOHAHCE IK CHBKICJhL FHIBIC8 A Modified Pulsed field Gradient T^lmi^c tur Ta.S.mBBMV. Institute of Caeaical RiysicB 117334,llowow,roBR Measuring Diffusion in the Pte&envU oi tUc ground Magnetic Field Gradients Chemical and biological BIB ia dealing now with centimetre I.. J. Lowe and B- F. Ranic-li, Jr. wan band. Heanwfclle, the SaV-lika Ugh resolution conditions Univ. of ritcaburgh, Pittaburgh, PA I52fit), USA may be asbltnd in 8Bt onlj at X»1-3 m. The aia of this ooaamnioatioa it to dtaonatrat* the new posnibilities union The diEEuslua coefficient ([)) of iiydrugcn In paudertnl humpies u t mt!la I ?!-~'i* -'." origin, xrom mastering the auballllaetre wan dlopaioni hydrides mumt often be ufcasur.-d In the presence of Urge Internallyprodneed Wen Experimental Haw application* aagnetlc field gradicnLc (c ). Me have modified tlm regular pnl»cd L! (1) band realisation. Kradlenc (PFC) cechnlque co remove the elffi=ta of i:o on the meaat] nt uf 1 BB OB spectromstre Spectral resolution of organic ra- D. The new pulse sequence combines a Cirr-Purcel! " btriiin ot IRU* (J..2 mm) with dicals in solution.Spin baalltonisn puliu that ameliorates the effects of CQ on the eclio amplltnde witli ft Bnp#rc ondiifi "tri ng paraaetrea from powder and glassy dltcrnjtlng pulsed field t^radlurtt (APFt.) de^uetice of magnitude C.^, •nm echo spectra.5xpanslon of frequency amplitude uence o: L.G.Oransky, Ta.S.LebedST, Doklady Acsd.Hauk SESR, 250, j 180 U/cra applied background gradient. We have ubtd the Lethntq.n; to raeuai 68* (1976). [J for hydrogen tn HfV2 hydride poudet, u ^ymam u-ith a large^partlcle alie 3. B.T.Broode, Tu.lt.Gorahenson, A.V.Gorellk, C.D.Il'ln, related^'. . C .AjColesnlkoT. Ya.S.LebsdaT, L.X.Solov'eva, Einetica 1 oatalii, 19i lc.2 (1978). 1. E. O. Ste]akal and J. E. Tanner, .1. Ui=ci. I'liyt.. 42^, 288 (1965). 4. S«V.Broude, Tu.H.GershenBoni C.D.Il'in, C.A.KolesnlkOT, 2. 11. V. Carr & E. H. Puree11, Phya. Hav. V4, o30 (1954), Ta.8.tabedoY, Soklaay AcadJUuk SSSR, •&», 366 (1976).

D4JQ3 Dt3(W A BBSWUCS QHASI-OPIICAL POLARUIETER TEE 031 OF KB USES TOE EURICS AID MECBAlTSa' 0? BLBIBVIARX KB I50GU UIBtEnC 3PBCIE0METERS AfOKC-anraiTLaB CBmCAL 2B0CES3IS STBD1ES A.A.T8HTO. lu.P.POFKOV aad V.P.SHBSTOPAIOT, Institute of B.B.QQBDQg. A.P.SEBMISOT. Institute of Chemical Rtyaics Badiophjsics tad Electronics of the Ukrainian Academy of (Branch) of the Academy of Sciences of the DS3B, 142432 Sciences, Kbarkor 310065. USSR •oseow Region. TJ.S.S.R.

The author* suggest a resonance, quasi-optical polarlaeter Vide poaalbilltiaa of aaaera baaed on the transfers essentially aaploylng an open resonator (OR) with compensations between hyperfins (HP) atom states to study kinetics and far the distortions in the resonant waTefront dua to finite di- mechanism of elementary chemical processes with these atoms aenaions of the saapls. Daing OR'a with a high Q-factor (about participation hava bean demonstrated with tha exaaple of 40x10* to 50x10') ana la able to •aasure aagnstle absorption in hydrogen atoaa and hydrogen Baser. Such an approach allows to the aaapla and analyaa the polarlaation and phase structure of obserre a Changs In B? atoaa states at their collisions with the fiald. Ihe phaaa ahlft in the transfer ratio at the resonan- tha studied iiolecules In gaaaoaa phase. Principles of reaU- ce, resulting from insertion of • saaple, ia proportional to the •ation of relaxational (when Baser serves aa seneitive spin O-faetor. Tnie prorlde* for high relaxoaeter in pulse regime) and frequency (based on aeasu- aanaltivity of the method in study- reaant of colliaional ahlft and broadening atom radiation ing aagnetlc properties of aaterlals. line) aetnod. nan been discussed. The figure ia a block-diagram of the Msaer radlaspectroscopio methods give an unique possibi- polarlaatar Incorporated in a magne- lity of studying the prooeaBfle at vary low atom concentrations tic apeetroaater operating at I50GHS (~10 oa~^) whan any secondary prooesssB may be neglected with and higher frequencies. The resonant certainty. These methods can be used Boat offectirely to study field polarisation can be determined rererse chasHcal reactions when traditional ones «"-e unfit. from the polarisation ellipse that Besides aeaaurtng the rat* constant of the process under la displayed automatically on the study one aay aeaaure 'aa well ooherenoe loss degree In the CRI of the oaoilloacope S. Other process (relaxatlonal method) and lifetime of intermediate unit* shown In the figure aret complex (frequency method). I - diffraction-radiation generator; The results of experimental Innstigations of model In 2- OB} } - sample; 4 - Soppier fre- reactlTlty theory reaction H + Bj —»• B2 + H (rate constant, quency shifter; 5 - phase corrector; the relation of ortho-para eonnrsion of aolecule and BT 6 - polarisation splitter; 7 - ware- relaxation of atoa to proton transfer, effect of Tibrational gttide bridge. exoitatien of aolsonl* on rate and path of the reaction) and the reactions of rwnra* addition of H atom to nonaaturated simple molcculee - primary acts of aejorlty of termolecular nhmrlnal raaotiana (formation rat* constant and lifetime of iiitermedlate complaxsa) are presented to Illustrate the aiTsntagea of the maser aathods.

~~B5U wcUu - •nctiu Donu moiuact. BS12 D1305 D1306 2 1811ATS BUD BFB OP HOg RADIOALB SELECTIVE EXCITATION IN FT NNR~~

~~O.Ta.Grlnbarg. A.A.Dubinaky, A.P.Morav»ky, V.P.Shuvalov, J.fOSiaR and J.PAST, Institute of Cybernetics of the~~

Ia.8.Lebeiev, Institute of Chsnioal Physios of the Aoaoemy Estonian Academy of Sciences, Tallinn 200001, USSR of Boiences of th* UBBB, 11733*. Moscow, D68S Fourier synthesized excitation of NMR 11] makes It possible to generate any desired spectral density distribution of the rf She special 2 an BPR apparatus for chemical investigations field uaed for spectrum registration. With minor hardware and /1/ had boea used to investigate BPE of HD2 radicals appoarins software modifications, it is possible to use commercial FT -NMil at 77°E photolysis of froien H20j/Hg0 solutions. In this unu- spectrometers to generate a sequence of pulses of constant ampli- sual wave diapaxon the liquid spectra resolution and solid stats tude and center spacing, but of varying width, determined by the spectra analysis sra often significantly improved /2/. For HO2 Fourier transform of the desired spectral density function. A radical the resonacas corresponding to canonio g-tensor series of about 1O0O such pulses, delivered during a time t

1.A.A.0allin, O.Xa.Grinberg et al., Fribory 1 tochnika 1. Tomlinson.B.L. and Hill.H.D. J. chem. Phys. 59, 1775 (197i). experiments, Ho.4, 284 (1377). 2. Bodenhausen,G.f Freeman,K. and Morris,G.A. J. Kagn. Resonance

~~2. O*Ya.Grinberg, A.A.Dubinslry, V.F.3huvalov, V.I.Karochfrin, 23, 171 (1976).~~

~~•L.G.QranBlqr, Ya.S.lebedeir, Doklady Acad. llaut SSSH, 230, 88* (1376).~~

D4307 D4308 TIME RESOLVED ESR SPECTROSCOFY USIBG A STOPPED-PLOW TECHHIQUE AIPIIOAIKB OF LA3«a POLAEDBHB 10 UCB0IAU SFECTHOSCOPT EJiiimiMW.TJiZlMsm. state Optioal Institute, G. lASSmBH. H. K1IHES and B. EBERT, Leningrad 199164.D3SH Central Institute of Molecular Biologya Academy of Sciences of GDB, DDR-1115 Berlin the application of «««net»-optioal methods to aiorowave opeo- trosoopy is possibla do* to the direot relation between the c- A new stopped-flow apparatus was developped and adapted to term of the Faraday effeot (or MOD) and the magnetisation of the an £SR spectrometer (VARXAH E3) allowing the observation of Bpla-eysten. the laser poiarimeter with the BanaltiTity 10 changes of ESR signals ss a function of time sfter rspid w4-w-fTig *"C"'1HW seo./i/ nctands oonsidarably th« poBsibilitlBB of msaao* of two liquid reaetant systems containing paramagnetic csntera. resents sf small magnetlsatiDn variations sad is expected to Typical biological demands as small consumption of substsnee increase substantially the rola of the optioal Methods in mioro- were taken into account. The time resolution of the stopped-flow wave speotrosoopy of solidfl. It 1B important to note that the ESR apparatus is 2 msec. The apparatus is suitable to measure probe laser beam passing through the Bedina in transparency re- rate constants of formation, conversion and decay of free radi- gion even at eufiielently Ugh Intensity (aeoessary to achieve cals, especially with chemical reactions in the liquid state, high sensitivity of polaxlaatrio •eaauraaants) doss not disturb {informational changes of spin-labelled biopolymers can be resol- the population distribution ovsr the msgnetlo sublevals of the ved klnetlcally In the millisecond region by observing the time ground paramagnetic state. It is shean that the restrictions of dependence of certain amplitudes of the ESB spectrum of the the method oonneottd with the fixed value of the laser wave- bound nitroiide label after initiation of structural changes length are not of great importance, the possibilities of the la- in the biopolymer. Application of the system is demonstrated ser polarlmster aathed are illustrated by the experimental stu- with the decay of ascorbic acid radicals and with a pH-induced dy of leFj-ra2* BSB speotra in low msgnetlo fields (flg.1). A confoxnational change in spin-labelled serum albumin* nigh sensitive aodulatlon aagnsto-optloal method is developed and applied to the investigation of the oroas-relaiatlon proceeses over the isowru. ground state superfine structure eub- levels of the n2* ions in flnorite typo oryatala. Ihe aenaltlvity of the laser polariaater method is dleoussed In comparison with that of traditional ml- orowave MS method.-

~~0 100 200 H,rc flg.1 1. AUiandrov >.B.,Xapaeakll T.S.0pt.3peotroek.41,855(1976).~~

V 04310 NUCLEAR. SPIN POLAAIWTM VIA THE LAMB-SHIFT STUDY OF RELAXATION PHENOMENA BY ANALYSIS OP EXPONENTIAL Tu.A.Pliss. L.H.Soroko, Laboratory of Nuclear problem*, Joint HDLTICOHPOHBHTS DECAY CURVES. AN APPLICATION TO DIELECTRIC Institute for Nuclear Research. Head Prat Office. P.O.Box 79 . SPECTRA Ibwg., 101000. OSSft Y.BALCOD. Crystalline Physics Group, University of Rennes. Until recently there has been no devices capable of measuring France particle spin polarisation without accelerating particle* up to HeV energies.. The first such devices, namely, a nuclear npin pola- Relaxation phenomena may often be studied in terms of expo- rimeter via the Lamb-shift operating at ion energies in the KeV nential nmlticomponents decay curves. region i* described. The principle is based on the relation be- He analysed the dielectric behaviour of a polysubstituted tween the populations of the hyperf ine substates of the ZSwj benzene by improving /I/ the method proposed by Gardner, Gardner, •etaatable state and the spin polarisation of the nucleus, protons Laush and Helnke /2/ for extracting components from such expo- or deuterona, of these mstsstable atoew /I/. In the device polar- nential functions. ised protons pass through the cesium cell and aa a result of the The method consists in using a convenient variable change, charge exchange at the entrance of the Helmhots coils the beam followed by a Fourier transform, a division by the eulerlan r consists partly of faat atoms in the 23j#2 atate. Due to the cross- function, then an inverse Fourier transform. It furnishes simul- lavala in ing of the 2S]/2 and IPwj *hm magnetic field 574 G the taneously the relaxation tines and corresponding amplitudes under metaatabla atomic levels 2Sj,2 undergo a decay accompanied by the form of Heavyside's step functions. the emission of Lyman photons A - 1216 A , which are detected . by s photon counter. The spin polarisation p is determined as 1. BalCOU.Y, C.R. Acad. Sci. Paris 284 B, 89 (1977).

~~follows /2/t 2. Gardner,D.G,r Gardner,J,C.f Laush,G. and Heinke.w.w. J. Chem. Phys. 31, 978 (19S9). P-l ( 1 - x/~~

where X " and S+ are counting rates for unpalariied and polarised beasts, x •» B/B . B is the magnetic, field inaide the cesium cell, and B •• 63.4 G for hydrogen. The experimentally measured polarisation is P - 0.93. * -

~~1. Clsusnitser. G. and Fick, D. Kucl.Inatr. and Heth.47,171(1967). 2. Pliss, Yu.A. and Sorolco, L.M. Nuclear Instr. and Heth. 135. 497 (1976).~~

~~D13U D4312 KKK mat TiwunniT. SHE06X OF X miClSi& tfKH IU3SS BBSGLTTEICal BHB SFBOTBOSCOPT~~

r;v TT.^T»pii¥TT . » mwriTcnrm Labudar Tu.SJlOBSIlBIlHOT, JL.H.aOSN0T and S.D.V1HL1H07, Physical of Plqrsles of tha Aeadur of Scianoae of DSSB, Mooeow Depaxtaant of H.T.LcaoDoaoT lloacow stata University, Moscow 117234, DB8R 117924, 03SB , Baganaiation of loaesa in apin syatam wiCu the holp of linear * Ona or tba liaLtljog faetora In T£ apaatxaaeopy - nonmt- poaitive feed back givaa tha possibility to cause steady multi- faia broadralog - la studlad t\l aa a aonrea of tha dmaaloal fxeguency spin oacillationa with transitions frequencies. U)ol of instability of apln oaolllatora and noclaar laaaaa oasani.Fxo- tha systen /1,2/, Toe •aaanreaant of differential frequencies i(JJlK=CUai-UJ

~~D512 D4313 Dt31t TRANSIENT EPR SIGNALS IN SOLVING SOME PROBLEMS OP 5SIHSIKHT HDIiTICaS I* HBIKBOWniAH SEPARATING PARAMAGNETIC CENTERS SPXK ST8TBXB~~

~~J.RYABIKIN, B.A1IMBEK, S.PIVOVAROV. and A.POLYAKOV, Institute Ot Electrical Engineering Institute, Nuclear Physics of the Academy o( Sciences of KazSSR, Alma-Ata. 197022, USSR 4fl00B2, USSR.~~

The separation at individual spectra conditioned by different para- According to Torrey /1/p transient natations of the •sgneti- magnetic centers from the summary spectrum appears a con^ilicated but aation Taotor are excited by poise nrlation of any external pa- an "fft* '"1 problem. Attempts were made to solve some of the aspects af raMtere which govern the Btsady state of a spin systssi. in this problem by using poise modulation ( PM) Ot the SHF field. Frequency oonpled spin system it appears poasibls to excite the transi- onU pt»ase characteristics of the transitory part of spin-system response ent notation of the aBgnstisatlon Taetor of one kind of ap-.'-J fey to Iho periodic pulse excitation of the resonance conditions (wve been fondng the nonaquxlibrium energy lerel population of another investigated. The corresponding EPR signals may be expressed as: kind of spins. Hacher and Laroff /2/ dewmstratad it tor a coupled eleotronoclear aystaat with absaically induced dynasts; {4) +

D131B PHASE SHIFTER AND AHFLItUDE DETECTOR USE OF NUCLEAR MAGNETIC RESONANCE FOR MEASUREMENTS FOR PULSED NHR RECEIVERS OF PHYSICAL QUANTITIES V.HIHELE and B.IASCULOVICI, Institute for Physics and Nuclear S.A.SPERTOR, Leningrad Polytechnic Institute, Leningrad Engineering, Central Institute of Physics Bucharest, ROMANIA 195251, USSR

A pa&Mvz phaiZthiUii- (PS) with A»s:360o is described (flg.l Nuclear magnetic resonance {NMR) which i& widely used for actual size). The PS Is based on an artificial delay line, termi- studying the structure of substances, and for a number of other nated on its characteristic inpedance. The external coil, iroving physical and chemical investigations, may be successfully employ- along the line picks up a constant e.m.f. with the phase linearly ed to improve the accuracy of measurements of many physical quan- +tm COU. tities. High metrological characteristics of the NMR method are based on the strictly J inear dependence of the precession frequency of nuclei on magnetic induction. reo Fundamental principles of designing digital and analog instruments based on the use of spin transducers ?.re considered. dependent on Its po9ition:fl»- 36O°xl/L. A mechanical (^multipli- Evaluation of the accuracy of such means of measurements is qiven. cation df the external coll position assures the required phase It is shown that the use of NMR makes it possible to design sensi- resolution. The PS is easy to construct, can be designed for any tive precision instruments for the measurement of a number of fixed frequency used in pulsed NMR and proved to be very stable. electrical and non-electrical quantities over a wide range of A high tintMity amplitudi dttzctgn .working at weafc signals change, and under some specific conditions where other methods is obtained In the following way (fig. 2). Nearly all pulsed NHR are difficult to apply. Digital instruments with automatic tuning spectrometers are equipped with to the NMR frequency by a combined tracking system with Hall phase sensitive detection (PSD).PSD transducers are described. has a very linear behaviour star- The problem of building a primary standard for reproduction ting from weak signals and increa- of ampere through the precession frequency of protons is consider- ses the signal/noise ratio. These ed. It is shown that the use of NMR makes it possible to increase advantages can be extended to ampli- the accuracy and reliability at Lhe reproduction of timpeix- as tude detection by creating a refe- well as other electrical and magnetic units. AD-amplitude detection. rence in phase with the incoming PSD-phase sensitive detec- signal in a PLL system /I/and using tlon.PA-preanpllfier.PLL> it In the conventional PSD.The sys- phase-lock-loop. VCO* vol- tem works from lmv of r.f. signal tage controlled oscillator. Instead of about looirV, required by PS»phaseshJ. f ter • a classicol diode detection.This al- Pig.2. lows a good ballance between the r.f. gain (60 dB) and the video gain (60 dB) thus obtaining stable, linear and wide dynamic receiver system. 1. SXGHETICS CORP. Digital, Linear, KOS Applications. 1974. D4317 D4318 A MAGHETIC RE30KASCB STUDY OP CESIUM VAPOUR WITH THE USE USBB PROPERTIES TOR UPROVBHm OF USSR U10HET1C RB30HAHCB 07 SEMICONDUCTOR USER IRRADIATION SfECTROMBlSR SBRSITIVXXY H.ICT3IATCA. H.KABURIH,. A.KQTKIH, B.MALYSKE7, G.PAK and Yu.ll.OgBSUSHtOH.B.L.LIYSHIIZ. Institute of Chemical Physios, R.UHARKH0DZHAE7, Institute of .Nuclear Physios, M.V.Loaonoeov Ae«d.Scl.US3R, Moscow! USSR Moscow State University, HoBCOW 117234, USSR* Low pressure gaa lasers are employed ic laser magnetic reso- Cesium vapour magnetic reeonance haB beeu atudied with the uae of optical punping and with indication of resonance signals nance spectrometers (IHR3). Two modifications of registratin are from a gaseoue-diBcharge eleotrodeleaa lamp and from a amicon- used! (a) one-pass absorption ', (b) intra-cavity absorption z ductor laser. when the gaa investigated is placid into the laser cavity. To The semiconductor l&aer used was operated in continuous mode at near liquid nitrogen temperatures-. Rough adjustment of the la- improve the IHRS sensitivity magnetio field nodulation ia used. Ber frequency WDB porforaed by temperature stabilization, and To elucidate the principal ways of this improvement the express- fine adjustment using both Fabry-Ferot etalbh and the cesium ions for the sensitivity of MRS arc obtained here. These exp- resonance oignal. Magnetic reeonance indication waa performed with coherent ressions are baaed on analysis of laaer kinetic equation (singlo resonance and nonreaonance irradiation ao that signals were mode operation). It ia shown that in oase of low-frequency adia- registered by absorption and by Pared ay effect. batie modulation there is unexplored method of intra-cavity IMRS The possibility of detection of reaonance signalB using the Hach-Zender interferometer with operating cell containing sensitivity improvement- 2few supersensitive technique is proposed. ciaium vapour in one of the bridge arms iB diacusaed. Cesium It implies the uae of magnetic modulation frequency equal to that atomic magnetic momenta are oriented from both gaBeoue diacharge of laser intensity relaxation oscillations. The sensitivity of lamp and semiconductor laser coherent irradiation. ideal INRS may then reach 10"13 cm"1 or 104 part/cm3 (if its noise ia controlled by the detector quantum noise )1

~~1. S.V.Broude, Yu.M.GershenBon, S.D.Il'in.S.A.Kolesnikov, la.S.Lebedev; Dokl.AH SSSR, 22J. 386 (1975) 2. J.S.Wells, E.U.Evenaon; Rev.Sci.InBtr. ,£1,, 226 (1970)~~

D4319 D1320 COHYERSIOS OF AH E-3 ESR SPECTROMETER TRANSITIOB IS SW TO DETECT THE SECOHD, THIRD AHD FOUHTH HARMOHIC OF ABSORMIOH E.KSEHKO*.r.CHEHEMiraKH. I.V.Kurchatov Institute of Ato- D«Schwarz, N.Klijoesa Central Institute for Itolecular mic Energy, 123182, USSR Biology, Academy of Sciences of GDR, 1115 Berlin, GDE The observation technique of HMR multiple-resonance transition and the investigation of vector behavior of the resultant The conversion of an E-3 ESR spectrometer based on an Inde- magnetization for running water in magnetic fielda with the indu- pendent nodulation system for 50, 33.3 and 25 kHz field modu- ction from 5-10"* to 1-10"2! at different orientations of cons- lation is described. This was realized by a x'tase shifter, fre- tant B and variable Bj magnetic fields, concerning each other quency dividers, active filters and an additional amplifier. o is described is th« woric* Employing the polarisation of magnetio The standard operational mode of 100 kHz modulation of the S-3 moments of nuclei in -the field of superconducting solenoid with is not affected by this extension. The details of ths exten- the induction 7,01, has been obtained the signal-to-noise ration sion are described, we demonstrate the versatility of theae at about 50, nitt the length of coupling pipes 5 aeters. modifications to study very slow tumbling spin labelled molecules (see also /1/) as human serum'albumin and the microso- The lead screen at temperature 4,2°K (I3450 mm 0 «65 sr.'i) oal cytochrome p450 syatem (by Beoond harmonic detection of is used to avoid the influence of scattering field* the absorption 'out of phase") as well as the resolution en- Registration of resonance transitions was made by TORana - hancement achieved by the third harmonic detection • in phase1. lyier /1 / , from the outlet of which, the signal through the amplifier qith the phase disoriminator was tranafered to the Y inlet of tne recording; the voltage proportional to the freqtienoy 1. Thomas,D.D.,Dalton,Ii.R.,Hyde,J.S. J.Ohem.FhyB. 65,3006(1976) t of the alternating-field generator is transfered to the Z inlet. The quantity of resonance transitions, depending on the experiment conditions may be of the order 50. Howtrar, the equation / 2/ nco m jr3a (where n-i ,2,3 .... a; - frequency of the first resonance) is carried out only at definite relations between BQ and B^ • The variety of tlte observed eff«ats (the dis- turbance of the frequency in the position of resonance peaks, degenerany of resonance transitions, the oecurance of wide resonance peaks in the field or low (~ 100 Hi) frequencies and etc*) an not considered in the work / 3 / .

1. lyBBnko, S. Priborj i Tennika Experiments, 1977, N 1, p.222. 2. Hiking, S. Z.fhysik, 19b3, 173, p.VsO. 3. Winter J.Compt.Rend, 1955, 241, p.375. D4321 D4322 THE RADIOPREqUENCY COIL DESIGN FOR CONTINOUS-UAUE NQR OR .HMR OF oscnunai raanssw SPECTROMETERS H S1BCTB01 SUSHI BX ESB KBIHOtt an ffhemi ftal-JTft J.Lufnik. Z.Trontelj. Institute of Mathematics, Physics and Mecha- Institute. Kazan 420015, US3B nics, and Physics Department* University of Ljubljana, Ljubljana! P.O. Box 543, Yugoslavia B3R Method presenta a large poBBlblUty fox Investigation of In an NQR or NHR experiment with a cw spectrometer it 1s often po- aai properties In a magnstla field / I / boasuse It may give ssible to foprave the signal to noise (s/n) ratio just with a pro- Information about eleotron concentration n0, electron temperatu- per tank circuit coil design. Since the NQR or NMR signal intensi- re 7gt oselHatlana and waTea In plasma and so on. E8R method.in ty is proportional to the Q factor of the coil, it Is advisable to aaaparlflon with wwrtnftT methods la eharaotarlMd by **#*«"• sensl- ' use coils with a maximal Q factors. However, one is always limited tlvity and by. higher precision of determination of the particle with-the size ofthe saraple"(in order to keep-.the fill.ing factor - concentration. ^ .„"-,.- _:„ . ^ _ /_ -.:-',•_: _.' .-'-• ; : close to 1), as well as with the desired value of the inductance L Successful application of ESB method far Investigation of (if of the' coil. Taking into acount this limitations, the Q factor de- electron plasma parameters 1B reported In this paper. Iha osoU. pendence on the parameter's* that characterize the rf coil, has been latlan processes In a spatial negative ohtxgo of toe vmonna diode analysed. Several sets of coils.for different frequency intervals, located in cylindrical resonator of the unprrhrterodjna spectro- with different diameters 0, lenghts 1, and different wire thickne- meter fig 1302 ( the work fre«nener-9>? OBi ) were Investigated. sses were wound. Their Q factors and inductances L were measured' ihe obeezred naon&nee speotroa deBStibes longitudinal with a Rohde Schwarz Q meter (Type QVH.BN 3672). The agreement •leotran WSTBO and consists of Mjaamul i Inrt series of the, lines 104 tB with the calculated values was within IQX. The limits far the geo- around electron gyration rrequonor S- i subhaimpniOB. / 2 3 lB metrical data for coils which should lead to an optimal NQR or NHR Position of Bpeoferai Unas In case U*« V « SI? > I signal in the frequency range 3 to 30 MHz were found to be: desoxlbed ij the following formula: £2± 0*5 £ 1/D S 1*5 and •1""5 d s 5 £ 1-7 d s oonatant, Where S is the spacing between two neighbor turns. m*eleetron aaaa, n -r,s,3...-haraonlc nmber* The copper Hires which were used to wind our coils had diameters Slaotron temperature Is defined by the anode tension Va of 0'4 mm s d s 2'Q mm. The diameter of colls varied from I'6 to end, for example, equals "7,-23 ev far k^-IOO T. Electron con- 5*0 cm. To confirm our conclusions we measured the >5C1 NQR signal centration In case u;0»V ni determine* from, diagram bit Intensities in NaClOi with different coils and good agreement with dependence Ul(Va) and was found edual rto-I»8'I0 -^jj . the predicted values was obtained. I. M. lammiil. Ihyslos letters, 301, 423 (1969) S. Ira.B. Bernstein. JhyB. an., 109, 10 (1958) . 3. a.C,DaTldiion and I.JUtrail. Phyu, HBT. let., 22, 833 (1969)

~~<-'&'. ','2"~~

D1323 of tfae Nuclear Spin System with the Radlofrequency locking Held,' A.A. Lundln. Institute of Chemical Physics Acad. sd. USSR, Uoe- cow, 117334, USSR; V.E. Zobov, I.V. Kyrenoky Institute of Hqr- sice, Siberian Departmnht Acad.Scl. USSR, Krasnoyarsk, 660036, USSR. She behaviour of the nuclear spin eystem in a radlofrequency (R?) field (resonant sad nonresonant) locking field was studied (the oscillations of magnetisation of the sample obtained in a rotating frame (HJS^, whin quaaitquilibriun sets in). By the cano- nical transform «^E HtS)-t have demonstrated that the projection of magnltlBation on RF field In 573 is:

Bie recurrent relations for £t«rt found. Thoy Involves the asymptotical aeries for all values of zq.(I). ihe parameter of series is^j- ;/4 -is the EP field amplitude, 1^ -is the local field acting on the spins. Ifj£

I D4401 D4402 A SHUT OT COaTIGORAXIOHS OT CICIIC COaTOUHDS wiTE IOW FOURIER TRAHSPORU IWVESTIGATI01J3 07 C-13 LABEtLED eOHOBHAlIO>AX BOSSIES THOM TEKEERAHJEK IBPDDKHCI3 Or SIML ADD STAHBYL ACBTY1EUE5 THHH 1H BUB SKCXBA. CTOOxaTBASIIAZAlBS K. KA1QSHSKA-TRBLA, Inatitute of Organic Ohemiatry, Polish B.D.LAVHDmiH. •e.V.BTBIXZaVA, B.A.ASTAOV. A.A.2HDABOT Academy of Sciences, 00961 Warsaw, Kasprzaka 44, Poland Institute of Organo-nement Compounds of the USSR Academy of SolsneeB, Hosoow 117813, USSR The charaoter of bonding between carbon and the group IT elements, as well as the electron dictribution changes in organic molecule Relative orientations of nethyl and phenyl grouse In cjrolo- upon substitution with silicon or tin containing groups are a tatraallasaneB as wall aa in oyelotetraalloxanes studied earlier .aubject of a quickly growing number of experimental works and /1 and references cited therein/ markedly affaot methyl proton theoretical calculations. In this communication the reaulta of chemical shifts. However unlike with oycloalloxanas, ojolotetra- Fourier,transform BUR investigations of mono- and disubstituted sllasane methyl proton *^"«i ahiftB Qarrespondlng to various sllyl- and atannylacetylenes labelled with carbon-13 in acetyie- liomers and various metbyl group positions are not additive and nlc fragment are presented. It was found that the values of apin- show pronounced temperature dependences, similar violations of -spin coupling constants between acetylenic carbona very sharply addltivlty were observed by us in substituted eyolotrlsllasanes decrease In a series AlkjSlCCH, Alk3SnCsCE, Alk3SiCsCSlAlk3, /2/. By aualosy with the latter, we treat the observed phenomena Alk3SnC=CSnAlk3. .Theee data and the observed changes in the ge- in terms of eonxbrmatioiial effeeta due to atario lnterao^iona minal hetero atom -Aacetylenic carbon couplings suggest a very between Balky aubatltnants. If the aubatltuent oonformatlonal (strong p. -d, interaction between 17 electrons of the triple bond energies In eight- and six-asmbered silasanes have the sana or- ''and the vacant d orbitala of ailioon-and tin. der of magnitude, tbe ohamlnai ablft vs. xnvnrsa temperature de- pendenss should be linear. In that east the ehemleal shift Table. The" coupling'constants in C-13 labelled ailyl and values obtained by extrapolation to Infinite temperature should stannylacetylenee (in HE) be additive. Th» experimental data are In satisfactory agreement Compound JI11C2I 'J(HC1) with the theoretical predictions. Tbe increments to methyl pro- HCsCH /1,2/ 171.5 .>> tonahleldlng from els- and trans-fbenyl groups at adjacent and 29 a a distant silicon atoms have toon calculated from the cbsmloal EtjSi-OSCH 130.9 75.0 18.6 shifts at infinite temperature. Scatter of the values thus ob- 119am Bu^Sn-CsCH 327.6 61.5 tained Is wall below that observed.for iaereaeata calculated 119.8 117* « from the spectra measured at some fixed temperature. These in- BUjSn-CaCH 119.8 313.1 58.8 orenenta'may he applied to assign aignala In various stereoiso- 29 i msrs of pbsnylsubstituted oyelotetrasilasanas from temperature 3s*" 101.4 74.8 11.5 dependences of their IHR spectra. 119* i 81.0 319.6 28.2 117M « 1. D.B.amiams, G.ll.Ronk and D.Splelvogel, J.Organoaetal.Cbea., Bu.Sn-C

04403 CALCULA2IOH 0? OTCItEAR HACHETIC EHIELDHIC 31P CHBilCAL SWTFI AKISOTROPY AND FH03FH0HUS OXYGEN BOND m SOME UOLECUIES A.-R. CRBMER. Zentralinstitut ftir anorganische Chemie der H.M.AJIIHOVA, Kazan State University, Kazan 420008, USSR II- Ad* der DDR, 1199 Berlin, DDR The method in which the gauge-invariant atomic orbitals are Powder pattern arising from the anisotropy of the chemical included in Slater determinant is applied for perturbed by mag- shift and the dipolar interaction are studied in phosphoryl- netic field wave function determination^ the integrals being Cir- halogonidoB and phosphates for 31P at different frequencies. culated by gaucfiian expansion of atomic orbitalB /I/. This appro- Components of the ohemical shift tenaor are determined. The ach allows to avoid the solution of Hartree-?oclc equations with orientation of this tenaor in relation to the oxygen ligand Z£gaetlc field perturbation contribution and to use the routine arrangement is derived from the known symmetry properties ground state v/ave function programmes and in fact is equivalent of the_environment, of the phosphorus nucleus. For the case to some variation method. It is shown to be a good approach for of an axialsymmetric tensor the aniaotropy 4? =? S"i[— 5j^ magnetic shielding coJStonte calculations for the light nuclei. is shown to be correlated to the lengths of the phosphorus Such calculations -using Raneil's SCP MO LCAO functions were car- oxygen bond, high yaluea of As corresponds to short phos- ried out for diatomic molecules CLiK, HP, LiP, BH, Hg) the proton phorus oxygen distances. The ahortening of bond lengths and lithxum magnetic shielding constants obtained being compa - relative to the single bond distances is the wellknown reble with results of more couple* methods. Good -results were experimental proof for tba existence of multiple bond. nbtained for the absolute proton magnetic shielding constants Therefore the determination of 4(" provides useful infor- " in* some phosphorous'Siolecules- uuliig CHDO unperturbed wave func- mations about the distribution of multiple bond character tion and also for cyclohexane end dioron solecules employing EHT in phosphorus oxygen compounds. The application of this wave function. As regards the magnetic shielding calculations of results to compounds with unknown character of the phos- heavy nuclei, it ia necessary to apply more complicated variati- phorus oxygen bond will he presented and discussed. onal function to take into consideration the perturbation by magnetic field.

~~1. yminova, Ii.H. Dokl. Akad. IJauk SSSR, 219, 625 (1974).~~

Fedotov, Yu. B232O Goldacker, W. A413 D4405 CjIUSMTiTITJ BSTUUIICH Of TIB GBCDI1L MTEUCTIOH TH PROTON, CMBOK MD CADHIUH NWt HEASUREHEHTS AND KELATIVISTIC CALCULATION OF OSBiHIC JOn> ttTAIAOOBCiHIC HOQBC1HSS THE CAOHIIM-CAMOH COUPLING TENSOR IN OIHETHH. CAOHIUK T.P.TEBIH. p.ijnnmr, •.'cvmaanor, mstituto or organic IC. WilsXMtll md J- JOKISJWII, OeiurtKit of Physics, University of Oulu, Chomlatrji Slborlan StrUion of too USSR Acadtwf of Seitncoo, 90100 Olilu 10. Finland 664033-Iikatsk, USSR H.B.7ITE0TBSATA, ViB.SJBICHW, Irkutsk stat« OalTersitjr, L. LUUNEN and A. PA55OJA, Depsnnent of Chemistry. University of Oulu, Irtatok, DS&B 30100 Oulu 10, Finland

9w through-space Interaction of atoi U and|C-Cl bond alect- P. PIVKKt), Department of Physical Chemistry, «txj akadcml. 20500 *bo (Turku) B0, tons (eaalaal Interaction) in «olecul»a with Cl-C-M (J-C-IO group Finland was found to provide ths aooulous electron density distribution The natural abundance V, ^C, n>Cd and ' 1^Crt HMR spectra of dimethyl that doss not correspond to the isductiva offset oi' atoa H or any cadmlua In Isotroplc and anlsotroplc phases have been recorded and analysed. other eobstitumt with this atoa /1/, We eat a technique foe The solvent dependence of the Cd-H and Cd-C co-jpllng constants was studied. quantitative oatiaation of gorinal interaction influanca us th» The values obtained In neat liquid and in d,-benzcne are practically the sane, "Cl H SBSy SiBj, Si(C^)3, etc.). *e hare also carried coupling. The C3dnituiir>carbon distance Mas solved with the aid of the ^C out quantuB-aechanical calculations of tua CNDO/2 typo for all spectra in nematlc phase, and using this distance the anlsotrupy of the Cd-C thaaa aolecuXes* fhe results of both calculations go together coupling constant was determined. The experimental value of 0.350 for the well and have the good asreeaest with the experimental '5C1 H^p relative anlsotropy. &K' - (Kll~ Kj)/K, li smaller than the value of D.fc?M35) spectra of the compounds under considaration. The data received obtained fo> dimethyl mercury. This agrees with the theoretical relativlstlc do eoKfira .the previous conclusion IM that the anoaalous pro- trend of 0.30 and 0.35 for Cd and Hg, respectively, and disagrees with the perties of the compounds containing the Cl-C-H. (7-&JI) group, identical non-reUtivistic values of 0.29 for both Cd and Hp. Thus the differ- which ara ueually aecountad for different conjugation effacts, ^nc-: of &K' betwren Cd and Hg may largely be of relatlvistlc origin. actually ace caused bj the ona and only iafluanco of atomic geai&al interactions in the case of any atom II,

~~1. H.G.VoronkoT, 7.P.Peshln, teg. Magnetic Bes., 9, 665 (1977) • a. T.P.Feshin, P.A.Niiitin, H.G.ToronfeOv, nokl. Akad. Haui SSSH, 338, 1W» (1978).~~

The structural aspects at pr^tonation these systames are con- aidHred, the 13C n-m.r, spectra of I-III are assigned and the ef- fBcts of protonatian an the V and 13H chemical shi-ffca and on the C- H coupling constants are prasantsd and discusaed. The structures of protonated and deprotonated forma of the antinooplaattc drugs "tomizin" and "pra3pldin" and psychotropic drug "pyrarldol" are proposed on the basis of these data.

Haavasoja, T. 152 Il'yasov, A.V. D25O6, A341O D4409 04410 Determination of Proton Chemical Shifte by Analyoie of 1H, 2D, 1JC mis ISVESTIGATIOH OF THE POCEHTIAL EHEEQI Intensitiee of Low Resolved Uultiplete in Off-Reaonanee BDBFACSS ABD 0? THE HtOTOS SXCBUIQS MECHUHSH5 THROUGH Decoupled Carbon-13 Spectra BYDROGEH EOHD ;

Q.QROSSUMn, Deportment of chemistry, Technical Uni»ersity H.H.BHAEBT'KO. tu.S.BOGACHEV, I.l.EADUBHlOVi, S.S.BERE8T0VA of Dreeden, 8027 Dreeden, CT)R and DtNiSHXGOBIN, L.Ya. Earpov Institutil of Physical I: i ChemiBtry, Moscow, 107120, USES A method for determination of proton chenical ahifta in Two methods ore suggested to determine information about substancee no poaaeaaing high reaolved proton apectra will be potential energy profile along the coordinate of the proton described, chemical ahifta of protona directly bonded with car- exchange reaction In the bydrogenbonded molecular systems. Thia con atoms can be determined by reduced coupling constants in the inforoatloa lnaludeB the number of potential energy minima, caae of well resolved off-resonance proton decoupled carbon-13 their positions on the reaction coordinate, their relative epectra /1-4/. If there are not off-reaonance apectra of the AX,, depths «aa the potential barriers heights. type it ia impoasible to recognize reduced coupling conetante The first method is bailed on the analysis of the deuterium in a simple way. Rowever, in theae cesee it is alao poaaible to isotope effects on the 1H, 2D, 1'o chemicel shifts. It is determine proton chemical ahifta ntmely by meana of analyaia of shown that the magnitudes and signs of the Isotope effects due the line intensity in the carbon-13 apectrum. For thia purpoae to deuterium substitution for the bridge hydrogen are determi- f frequency muat be changed near by the resonance frquency of ned by proton exchange through the thermal activation or tun- the concerning protons. The intensity of line in the carbon-13 neling mechanisms and by the ishape of the potential energe sur- apectrum obtains the maximal Talue if the f2 frequency ia iden- face. tically with the reaonance frequency. In a certain range below She second method includes analysis *C NUR chemical shifts and ebOTe of thia frequency the intensity changes in a linear in the molecular systems A-H.*.B and A-M...B, where H 1B an way with the off-resonance frequency. The po.int of intersection electron-with-drawing group (<>•£• B? ). It is shown that the of theee two extrapolated atraight lines will be accept as reso- 2 effects of U - substitution on "c chemical shifts are determi- nanee frequency of protona attached to the concerning carbon. ned by the difference In potential energy surface^ between H - The application of this method is shown by n-hexane, n-hexane- nTirt || « systems • phoephonic acid, and cyclohexanephoaphonic acid. Several mathe- matical procedures of evaluation of meaaurements and statistical Unlike the methods baueci on determination of temperature analyaia of results err; diacuased. depec4ences of HUR signals the methods suggested here are applicable to proton exchange processes irrespective of their rates. 1. Anderson,!.A. and Freeman,!). J. Chem. Fhys. 37, 85 11962). 2. Ernst,H.R. J. Ohem. Phys. 45, 3845 (1966). 3. Pachler.K.Q.R. J. Magn. Reson. 7, 442 (1972). 4. HacDonald,J.C. and Hazurek.M. J. Kegn. Reson. ?8, 181 (1977).

DM.1 D4112 C0RRBUT10IS BKIZZH STRBTCHHIC raEQUEHCIES AID SOME IHTJSRUOLECUJiAR EFFECTS OH HEBCORX-199 CHQHCA1 SHIFTS HQR OS m aDAHTITIK; BSPEHDIHQ OH THE BLECTROH SHELL m OBOASIHIEBCaaY COMPOOTDS PROPERTIES AHOUHD THE HZSROGEK HUCLEUS Yu.E.GRISHIH. Yu.A.USTYBYUK, Yu.A.STBELEKKO, O.K.30K0LIK0VA I.T.TuTHSYI and K.S. ZATSEEtHA, The State Institute end L.A.HAHGUL1S, BME Laboratory, Separtoont of Chemistry, of Applied Cheadatry, Leningrad, 19719a, USSR.- Moscow State University, lioscow 117234, It 1B demonstrated that for a large number of miscellaneous The chenical shifts in symmetrical organomercury compounds polystmie molecules the correlation oan be made between "averaged" RgHg where R is alkyl, aubatitnted slkyl, aryl are measured ia I-H stretching frequencies ( i)xu), where I-B, c, I, O, 7, and the- various solvents la the wide range of concentrations and tempera- oretical values of eleotrio field gradient at the deuteron (Cl'jj) tures by the 199Hg and 1E-(199Kg^ teebaiquea. tfhioh nave been ooapated sb Initlo S«C*F using a "double zeta* ba- Kercury-199 chemical shifts, S (Bg), of HSgHs and FhjHg vary •la at Oaoealan contrasted functions. Beoently a similar relation within 100 ppm in going from nonpolar solvents to polar aprotic wmm propoeed for two-atomic ionic hydrides only /I/. It appears that solvents which 1B scores of tines larger than what is observed 119 2u7 77 the neglecting the aeoond and the third terms of. the known Salem'e for S-( Sn) of He4sn, S( pb) of «e4Bb, S( Se) of He2Se. This farsnla /Z/ slves rise to amsll_miBber of notable exeptions* points to the mercury complexations is solutions. Relatively The correlation between D M values and geminal spin oou- small complex formation enthalpies for Ua^Bg ia benzene ( -0*5 pllng oonatantB Oaf la held fairly well for over 70 organic molecu- kcal/ool) and in nesityleca ( -0.7 kcal/mol) are indicative of les which cover a wide variety of bonding situatlons._The range of high sensitivity of meroury-199 shifts to eleotronic factors. 1 3CH variation due to changoe of OQJ is 60 Ez (&DCH^<4OO on" ). With arylmsraory derivatives (XCgH^gHg the solvent effects are She «ame trends are observed for proton-proton gemdnal coupling comparable with the sutatituent effects, the 199Hg ohemical constants JHH . The results indicate that the M-0. theory devised shift range increases considerably on going from inert solvents by Jople sad Bothnmr-By for JHH > •'CM constants can also be used to polar ones (by a factor of about 2 an going from CgE^g to to explain the observed changes of OCH Either an electronega- DHSO). In all solvents studied, the S(Hg) values correlate with tive group, a TT-eleotron system bonded to tne carbons-atom or s i the Honmett constants. ohange of the hybridisation of this atom leads to a qualitatively Selfaasociation of (CgHgCOgCH^gHg and (CHjCOgOHgCOOHjJjHg 2 •rtrrHBT ohange of 0w and JCH in the OOH entity. In contrast compounds in solutions has been studied. The monomer-dimer equi- a oubstituont with the lone pair orbitals at the first oxygen or - libria are characterized by the values OHM-2.4 kcol/mol, A3.-4 nitiogen atom (trans to an adjacent OH bond) haa opposite influence e.u. shd AEK-3,1 kcsl/mol, AS«-7 e.u., respectively. The tempe- on 5CH and JCH( ^HH) • From the results obtained it is dedu- rature dependences of the S(Hg) values for monoaeric species sug- ced that both fiqa and BKR coupling constants and the D^H valu- gest the possibility of metallotropic tautomerism t=i^=cu the es are mostly governed by the g-electron deneities at the adjacent C m and 0 • forms. ' nuclei. 1. Hokorram M., Ragle J.I. J.Chen.FhyB., 59, 2770 (1973). 2. Salem 1. ibid 38, 1227 (1963).

Kamienska-Trela. K _ am _ R . T . D11B D4414 •'-X noun - 77 us SWCTHOSCOIT. sera ASPECTS BXH2H!PZRICAL QUiBTQaVCBBllIOiL WSDO CALCULAIXOH 07 0? ORauosBiSMitm caHKraros BTTOT STKRSOOHElCOiL DKEBBDfflOS OF ^(BB), Z3(M), 5J(HB) Tilii'ViM" D.J.IU3HK1EB7, irkutak Stats University, Irkutek' EPIH-BPIH OOCELIHG COBEIAMfB 664003, USSR 7J.BMM and i.A.FAIHZIIi'B3HG, Instituta c* Organic OB •psetroacopy of Isotope 17S« (!•}, natural abundanoe 7.6H) ChemlBtr}' of tha TJSSR Acadanj of Sciences, lioeoow 117913, la an effective method for the structural investigation of ere»nooe- USSS lenldet which axa onaa of growing lnteraat In biopuyalce, medicine, Tha uBualljr uaed method of calculating coupling conatanta ehamietry ate. A/ does not take into account tha effects of the anlaotrop^ of 77 The solvent effect on the Se ebaaloal ahlfta la etudied for electron density distribution in tha electron intsxmetion energy compound* Bj-Se-Rj; Rj- and B2 axa group* with o( -carbon »ttm In computation, an affect that tells on the shape of the curres or en'-, *P •P-hybridlsation. Although tba range of variatloaa of depleting tha theoretical stareochemical dependences of tha "S. ahlfta Is anon compounds la nora than 500 PPB tba affaota of coupling constants. Since these dependences lie at the basis of tba solvents do not exoeed 15 • 20 ppa (tba raault of extrapolation tha structural Interpretation of the exp«rimei"«l coupling cons- to infinite diseolution for 26 aolventa). Xba analyses of tba ef- tants, we have carried out tha calculation of thd J(BH) coupling feota of polarity, polariiabUlty, nuoleopbilloity and alaetrophl- constants orer one, two and three bonds to: the HTOO method /2/ lielty of tha solventa on ^8a ahifta In aeaa unaatursted organoee- using the coupled variant /5/ of the Harcree-Toek perturbation lenidea ma well.as In (CB-JgSe uaod aa tha rafaranca compound for th«orji taking into account the 'contribution 00I7 of tba Vezai "a* apaotroaoopr dieplay domination of tha polarity term. contact tera. Iba "s. ohaaieal ahlfta asd XB - 773«, x;0 - 77as coupling The basic equations in the matrix form are as follows! conatanta through 1*4 bonda ara saaaurad for mora tban 100 aala- noaroaatlo osapounda, ir-3«-H. Tha direct obaarratlon of tha ^Sa In •onoraeoaanea or doubla raaonanea Sa - { H} oondltl^na aa 7777 II33 aa Indiroct aatboda % H { 3«}} apaetra 0 proton daeouplad apaetra, In It and CV moaa 1 ara naad-. Iha aanal- tlTity and aoouraoy of dlffarent methoda ara compared. Tha 773« ohealoal ahlfta and tha coupling conatanta ara found to ba very aenaltlta *to auch lntraaolacular atruotural fae- The aquation were oolvad by meanB of a Specially devised tora u S« - C bond charactar, molaoular conformation, aelanlua program in ALGOL-60 for the TTRTiM Ti, uncoupled alactron palra orientation and effacta of removed 8ub- The Btereocnemlcal dependences obtained have been caopeied atltuanta. Being obtained for tbe first tlae, tha aet of tha with tbe experimental values given In tha literature. I'o - ^Se coupling conatanta enablaa us to eyatematlia them. The axcallant correlation of direct coupling conatanta "c - ^Se and 'c - Tl proTea the contribution of the Fezal contact term 1. Pople, J.I. Uclver, J.C.Ostlung, B.S. J. Chem. Fhye,, 49, aa tha main one to tha former conatanta. 2960, 2965 (1968). 2. Pople, J.A. Beverldge, S.L. Approximate Molecular orbital Theory, He Graw-Hill, Hew Turk, 1970.

~~3. SteVBns,R.li. Pitzer,Rslia Llpscamb,*.]!. J.Chem.Fhys., 38, 550 (1963).~~

D1115 D1416 IC STBUC 1 ADD m STUDY OF THE COOTORUATIOHS OH H-ACETYL BT LCAO X-iLFA METHOD Ot-AKIBO ACID ESTERS IK 30LUTI0I P. HOvlK. Institute of Solid State Physics of Czechoslovak V.SLET.I.ARRO,T.LUIUSTE,Inetitute of Thermophyeiee and Electro* Academy of Sciences, 162 S3 Prague, Czechoslovakia phyalos of tha Estonian Academy of Soience,Tallinn ZO0105,USSR The H-KMR and 1R investigation of aoetyl oâalno acid esters Method originally developed for small (moBtly diatomic) in dilutu CC1, solution was carried out in order to study the molecules /I/ is applied to calculation or the electronic influence of various manna aaid side ohsins on the oonfornatlonsl 8tructure of permanganate ion. Gaussian basis sets conaiating aqullibrluB: open oonformatlo] of 14 s-type, 9p-type, 5d-type functions and 12s-type, 9p-typa with intranolaoulsr E-bond (C functions are usad for Mn and 0.respectively. The reaulta ob- 0 R 0 0 R tained are compared with Xcc -US and Hartrae-Fock ealculationa CHj-C-H-CH-0-B1 v CB:,-c-K-CH-f-O-R'. ' , where R"H, alkyl group or of the eamtr complex. The local approximationa to axchuga-'cor- 8 C relation tjerm other than X-alfa are diseusaad. open n> CH_-@ ,R'*alkyl group* In the eaae of ethyl eaters the violnal 1. Sambe, H.and Pelton, R.H. J. Chem. Phys. 62, 1122 (1975). B-a-d-S coupling conetanta (^'jgg) indicate, that increasing bulkinsss of the substitusnt It, whsrs R>B or alkyl groups, oauaes progrssslv* eut-of-planarity distortion of the E-bond stabilized cyola of tha êonfo. Atlon. Tha equilibrium constants Ct 'open tha oonft itlonal enthalpy dlffarenoies of the states C, £, âunVars adstsrwdnsa d by 2R spaatroBaopy methodi E CsZ CH^CE- CSCCS.)^ Vic i 5*0 6,4 7.9 8, 1 8,7 2,2 4.75 7.9 7, 1 6.35 5,7 0.65 0,8 1,5 1, 4 1.25 0,9 Comparison of tha Influence of tbe nature of various alkyl eutstfr tuents R end IT on tha ^"'gg values and on tha conformational

~~equilibrium C ge C|It indicates that R' had leas Influence on theaa parameters than B, and tha aubstituent B lnpsots- ths confa»~~

mational aquillbriiai|Halnly through stsrlo faotor* the monotonoum increase of tha ^"Jgg values and the nonmonotonous behavior of K and E values with the growth of alkyl substltuant R bulkinees indicates that ths influence of the subatitrnnt B Increasing bulk*, ness on ths above ccnf ormatlonal equilibrium is rsallzsd by two different manner) east 1)ths progreaalva out-of-planarlty distortion

~~of ths H-tond stabilized oyole destablliieB C(xt confarmation,~~

~~2) the inoraaae of the atablllty of tha CiTt conformation due to (zt tba Tharpe-Ingold affect.~~

KroDman. D. Toa-tn w T D4417 D4418 CUTLUIATIOHS OF ISOTOPIC EFFECTS OM SPIH BPIH COUPLING I30 HMR SPECHU Of MEIHYL5UB3TITUTED 2- AID 4- AZAP1U0HE118S. 1 13 CONSTAHTS 3CB AHD C CHEMICAL SHIFTS IH KETHAHE, S.I.SoloTtnov, r.P.Zvolinaky.Yu.H.luzilcov.A.A.Pomichev, EimfLENE AND ACHEOTLEHE V.F.Zakharov.V.G.Pleenakov, Yu.A.Uatynyulc XK.ORMBERDYZV, V.H.HAMAYEV and H.H.SBRGEYEV. .\. •- -1 HMR Laboratory, Department of Chemistry, Moscow State University, Hoicow, 117234, USSR The dependences of NHR paranetera (coupling constants, cheaical shifts) on bond length have been calculated at the IKDO The ^C-spectra of m»thylsubBtituted 2- and 4- aaafluoreneB and HINDO/2 levels of approximation The isotople effects have been havo been examined ( I - I ). To ensure unequivocal assignment determined from the results obtained geometrical model which re- lates isotopic effects to vibrational distances Rg and mean square of the I3C resonances, a combination of four different tecnniquos amplitudes I2 known from electron diffraction studies. {Table 1). was applied: a) *3C-£%$ - off-reaoaance noise-decoupled spectra; Table 1. b) proton-coupled 3C epectra and analysis of a long coupling The Isotopic Effects on the J(« coupling const I3 constanta between C and ^H; c) "fingerprint" method; d) Eu(fod)j 13C chemical shifts lastnanlde-inducad shift data7 Molecules Isotopic effects1 Chemical $•• Coupling constants, Hz shifts, ppmb

~~CH4 1.04 0.19 (1.07, 0.28) (0.24,. 0.01)~~

~~C2H4 1.56 0.18 (1.05, 0.51) (0.15, 0.03)~~

~~c2n2 2.33 0.10 (1.52, 0.81) (0.12, -0.02)~~

Die chemical shifts were interpreted in terss of total charge aThe IX,V) values in parentheses are the contributions from the densities calculated by CSD0/2-M-:nethod. An inaljsio of the linear (X) and quadratic (X) terms, respectively. steric and electronic effects ia given. For tne calculation of bPoaitive values correspond to upfield shifts.

~~chemical shifts ii asafluorenea and carbo- and heterocyclic The calculated isotopic shifts decrease from ca. 0.2 to 0.1~~

systems tne additivity scheme was employed.- vihile the isotopic effects on coupling constants JaI increase from ca. 1 to 2.5 Hz on going from methane through acetylene. The calculation results agree with the experimental data available.

D1119 13C MR SPESTRCS30PY 0? SOUS PIRIHIDUE 1TOCLE05IDES, 5'-A*F-dl-Ha-SAI.t, HAD4' AJID NADH-di-Na-SAlT. 3 13 3 13 THEAKALYSIS OP C0HPHBG COKSTASTS J afi-BJ, J C2-H^ 3 and V C8-H{ AID BOTABT ISOICEHISM ABOUT A GLYCOSIDIC SOHD

~~A.P.ABRJUIOV, Instituto of Physics,Byelorussian SSR Acadeaj of Soiencoa ,220602 Hinsk.USSlt~~

3 13 The analysis performed of spin ooupling conatanta J O6-H; , 3 13 3 13 13 J C2-Hj and J Ca-B] in C US cpaetn of (one pirinlolne (1-3) anoleoaldSB, S'-iMT-di-Sa-salt.irAD**!^ HADH allows the most populated oonToiastian about a glyoooidic bond to be speci- fied, tne effect la investigated of snbsiltWta (H.OH.Cl) at 0-2' of carbon aton sf a oarbohydrate fragment on ateric interactions between the oarbohydrate fragmnt and pirlmldins bate 3 13 and.aasooiated with thea.ohasges In J O6-Hj and chemical shifts. Also,a etuiy ia oade of an influence of the subutltii- •nts at a pirlatdise baa* In the> , r-poiition on storio in- teracticna between the carbohydrate fragment and pirlmldins baaa asd,aa a result,-vsriation of spin oousling constants, chenlcal abifta and toralGaal anglee of rotary isamsriam about a gljcosidio bend. Iheas data show the difference a in the rotary iBourides of heterocyclic baueo around a glycoaidic bond liable to oause the atructural direction of the reactlone in- volTlsg nucloosldea. Tna possibilities of a dlreotlanal change in the rotational lsomerim around a glynosldic bond due to the nature of electronegative aubatituente of C-21 os-rbohyd- rate fragiient and due to the B and y-positions of a pirlmidlne baa* an eaphasiied. tna pirimldine compouuda: ^-J-urldlna (1), 5-J-2'-desoiy- uridlne C2) and 5-J-2'-chlor-urldine (3> are Investigated. 1. AthrKi,A.A.,2ait>eva,(;.V.,lUkhsilopulo,J.A. and

~~AbrsiioY(A.*« J.Carbob3rarateafnueleoaideatKueleotldeB, 4,1,«-S3 (1977).~~

~~Malkin, B.Z. B1612 C24O1 Mitrofanov, K.P. B4311 CD t~~

~~CO CD~~

~~GO ia 152 in .olid. NMR EXPERIMENTS OH THE SUPBRFLUID PHASES OF 3He~~

J.Saidt T. HAAVASOJA, •' Laboratorium voor TeehniicUe H«ivurkimde. Techniiehe Hognctwol Delft, Low Temperature Laboratory* Helsinki University of Technology, SF-02150 Bspoo 15, Finland Delft t The Ketherlanda Vben tho rapid reorientationi or wthyl groups in lolidi are the dcnicant The NMR properties of the superfluld phases of 3He have been relaxation MchuiiM, in Addition to the wU-knewn Zecata and dipolar ayateas studied extensively in our laboratory over recent years. The work extra constanta of the notion occur. This is due to the fact that the spin that will be reported was done in collaboratorion with A.I. Ahonen, diffusion lwnm the populations unaffected of each or the A, Ea sod Bb T.A. Alvesalo, J. Kokko, H. Kruslus, O.V. Lounasmaa, H.A. Paalanen, •ynetry species characterising the Methyl groups. This has been called R.C. Richardson, and Y. Takano. Symnetry Restricted Spin Diffusion. As a result in general the Ztemmn and In our first experiments the susceptibility of the B phase was dipolar systetu are coupled dynamically to the rotmtional polariiation system, observed to stay finite in the zero temperature limit, thus excluding dafined as the population diffsreace between E* and £* species, and the pairing into an even orbital state. Later studies showed that the tunneling systen, defined as the population difference between the A tnd temperature dependence of the susceptibility was consistent with b (E* + E ) species. the orbitally symmetric Ballan-Werthamer state. In this talk the Zeesan relaxation will be considered at high tepperaturea, The orientational effect of boundaries and of an external mag- Mhexe the Zeeaan ayatee. is coupled only to the rotational polarixstion system. netic field on the B phase haq been measured In a flat slab geometry. It will oe abotm how the relaxation changes under the influenceaf: (i) sample The* results could be explained by a free energy contribution due to rotation; Cii) the preparation of the apin system before the relaxation; and bending of the order parameter and slight depairlng due to bounda- tili) the temperature. It is further inrastigated how the data characterising ries and an external magnetic field. In the A phase the effect of the methyl reorientations caa be obtained in the proper way from the •eaaure- boundaries was investigated in a stack of plates with an average menta. The results are compared with those obtained from the mecsureuents by distance of 4 um. The plate separation was obrsrved to be small interpreting them by the traditional BFP theory, where the existence of the enough to fix the orientation of the orbital part of the order rotational polarixstion system is ignored. Experimental- examples will be given parameter. The dlpole energy could be manipulated by selecting the of the Zeeaan relaxation of 2-wthyl piperarine and partially deuterated 1- orientation of the magnetic field. The longitudinal! resonance fre-

alanine, IDj CflCH^COO". quencies of the bulk h and B phases were measured down to 0.3 Tc at pressures between 32 and 21 bar. Textural defects in the A phase have been studied in the bulk liquid. Local inhomogeneitles in the order parameter have been 1. Said, S. and Hind, R.A., Chen. Ffiys. Lett.'27, 312 (I97fc) observed to develop by lnhomogeneous tipping of the magnetization 2. Eotf.0, 8., Bsarda., B-J., Sadat, J. and Hind,. B.A., Phyaica 9o B, 327 (197B) by pulsed HKR in a magnetic field gradient. 3. Wind, B.A., Enid. S-, Pournuie, J.F.J.H. and Smidt, J-, J. Phya. C 2» *39 As a separate project, the effect of boundaries on the sus- (1976) ceptibility of the normal liquid has been studied with pulsed NMR. K Wind, B.A-, Enid, S., PourquiS, J.F.J.M. and Studt. J., J. Chem. Phys. 67, . The boundary layers of 3He have been observed to behave as a quasi 21.36 (1977) two-dimensional ferromagnet.

155 154 THE PROGRESS IN SOLID-STATE WR, HMS OF CHIRM. MOLECULES A SOURCE OF HB> PROBLEMS IN LIQUID CRYSTALS E.I.FEOZH, Institute of Elemento-Orqanic Compounds, A.LO8CHE of th. Saktion Phyaik, K«rl-Harx-Unlvaraltlt,LalpilgflR Moscow 117813, USSR

In* th.raotropio liquid oryttajla nany problaaa. eonearnlng th. ordar or dynaaical propartlaa oar. aolvad by nr •athoda. Honovar, nan quaatloiu aroaa by th* raaulta of *H and 13C rnonano*, uhloh giva Inalghc Into th. aolaoular happening. - Tha dlpola-dlpola aplttttng of tha banzan. ring protona la uaad for 3S yaara for gattlng Inforaation about th. ordar In aaao- phaaaa. Tha. abtoluta yslusa critically do pond on tha banzana configuration. Nan aaaauraaanta of DrGRANDE in aaaollo-6 phaaaa and in aonooryatala of onpound* foralng aueh'phaaaat ylaldad Una apllttlnga. nhich oannot b* axplalnad In auoh a alspl* faahlon. - Faat Mr pulaa t.ohnlquaa aaka It poaalbl* to aaaaure tha raeovary tin of tha naaatic nrdar aftar dlffarant kind, of parturbatlona by obaarvation of th* FOI aignal*. Or^RALU found tha ehanga in tha Una ahapa to ba tha aaaa aa though a rotation of th* aftol* ipaelaan mr« to taka plaea. Th* Mporiaantally ' dataralnad raoriantatlon tiaiaa *r* proportional to ^ /*• . In oonneotlon alth nar &% -aaaauraaanta tha rotational vlaaoalty can b* obtalnad. - In araatlc phaaa* alac tha Una ahapa of th* proton doublat oeaponanta ahould glv* avldanoa of th* attribut- ion funetlon. but thla appaarad to b* lapoacibl* bacauaa tha llnm *ra broadanad by tha mtaraolacular dlpola-dlpola lntar- aotlon. Th* C apactra obtalnad fro* tha paw aathod by OrJJRAHDE ahon vary narro« Unaa. Accordingly tha. aaan valu* of th* distribution funetlon* auat b* rather aaall, »hioh contra- dleta tha npaotatton* fro* other axparlaanta. Further, thla . •athod anablet to obaarve tha oriantatlon of alioet each C-ato* In th* aolacuioa. Hence it «an ba aaan that aliphatic ohalne behave .in anothar ajay than tha central part*. - In aaactio phaeee th* carefully oriented epeciaan ae^ be treated aa a aonoeryet.l* It la r*th«r oonvenl.nt to lnveetlgete e.g. th* angular dependence of the hi raaonano*. Here a chartoterletic dlff.renoe batman aaeotlo-c and -A 1* obaerved. Fro* nar re.ulta thl* on only b. interpreted by • feat rotation in th* eaaotlc-A phte*. , . . A511 A512

~~UNUSUAL Wf> PHENOMENA IN CFCt2-CFCt2* THE STATE 0» WATER ADSORBED IS SKAIL PORES 0? MICROSCOPIC~~

HAtOLD T. STOKES and DAVID C. MUCH. Depart»ent of Physics, and DIAMETER ; C. H. HUC, Dvntnt of Chesistry, University of Utah, Salt Lake H.rfsifar. W.Qrttnder, Settlor. Phyelk der Kett-Msrx-Unlversittlt, City, Utah Mil! USA not-laboratory, DBR-701 leipslg. Daman Samooratio Republic

CFCl2-CFCt2 is a plastic crystal which is easily supercooled to a "ilassy" crystalline phase where the nolqcular orientations are froien Zeolites are poroua crystal* with s. wall-daflnad structure and in a disordered state. In the temperature relion where the l9F M« a high apeolflc aurfaoa araa. Thair'oooaoii formula, ia

relaxation tiaas (T,. T,g, T1D> and T;) an doainated by the aolecular ( A102 )" H* ( SiO2 )n + reorientations, we find that T} and T1(J are field independent on the hot wiloro U* danotaa an axohangaaUa oatlon like Ha and n la a number greater or aqual 1. For zaolitH of the MX or HY type the W1 side of their respective Minis*, as expected; however, on the cold side of the adniaa, we find a field dependence T, • H*" and T,D • «\" with rigid lattice la built up of SiO4 and A104 tetrahadra ataoked in n = 1.2, very auch different froai a BPP-type behavior (a - 2). In auoh a my that two interconnected pore ajatama result with a mean addition, the two sides of the T ainiaa are not syaaetrle but exhibit free diameter of 11.6 8 and 6.6 it for tha reapeetivs cagea /I/. a larger activation energy on th* hot side than on the cold side. On Beoauae each ailioon or •luainlua ion le aurrounded tatrahedrally

~~the other handi the two sides of the T{ Minisa are syawtTic with an by four larger oxygens, th« internal aurfaoaa eonslat of oijg«n,~~

activation energy in agreement with that of the cold side of the TJp the only other elemente axpoaed to adaorbatea being the exchangeable •dnia*. Possible explanations for these unusual features will be dis- cationa.Therefore theaa caolltea are attraotlva aollda on which to cussed. He also found in this* teBperature region a second relaxation . make atudiea of adaorptlon.

process which causes a "local ninimiB" in Tl as_ a_ function of-field. This An analjraia of proton relaxation for hydrated teolitea ahowa that process is probably due to cross relaxation with the 35Ct qundrupolar the algnala of aster moleoulea adaorbad in the small and in the

i'! splitting since we observed the Tt mniinuB to occur at about 40 HHz, a big cages oan be separated. The values for tha correlation tlmea typical valus of the 35Cl quadrupolar splitting in covalently bonded derived from minima, in tha temperature dependence of the longi- 35 ! £;:„ crystals. The Tx of C1. is probably very short in this region and thus tudinal relaxation times support the suggestion /2/ that tha dra- the effect on the T, of l3F would be limited only by the" cross relaxation atic reetriction of molecular mobility ia not caused by the exchan- + tine which is usually tegnierature independent, in agreenent with our geable cationn (at least far H« and K*) but by the rigid oxygen observations. * '.is cros,5 relaxation effect disappears at tenperatures lattice of the zeolite whlci atabilliaa water nsar it ("etaBlll- above the 40 mi T, ainimm of "F. zaticn affect"). A similar but much smaller affect has been observed in aqueous solutions of non-polar aoluta molaculaa and "This research has been supported by the U.S. National Science Foundation tunned structure-making influence of solutes /3/. Tha magnltudea under Grant OUR.'6-18966. of the correlation timea and their temperature dependenoea are compared with those for neat water and lee.

1. Brook!!).!*!. Zeolite Holecular Sieves, John Wiley & Sons,Hew York, London, 1974. t 2. Pfeifor.H. Physics Heports 260, So.7 (1976) 293-333, Uorth- Holland Publiahing Company, Amsterdam. 3. Prank.R.S. and Wen, W.-J. Diao.Farad.Soc 24, 133 (1957)

A 513 NATUKE OF THE PHASE TRANSITION IN HEXAKKINES J.Stankowakl.A.M.Betas. Institute of Holeculsr Physics PAS, - Poznari,Poland, University College,Cardiff,Great Britein The latest Rsaen, EHR snd MIR raeulte prove two,eBssntial ' kinds -of phaae traneltion, related with aolecular Motions of the cationa and anione, to occur in aastoniacatee. Tha high-tenper-

atura transition tj'f in aaaonlacates with a coaplex structure of the anion ia due to a change in tha notion dynanice. or an. ordering,- of tha aniona. The other, low-tenperature transition .for coaplex- aniona ~t/C^ la the only one occurring in aaaonlacatas'with spherical aniona, and is attributed by us to * change in tuabling oscillations of the complex cation. Z 1. EPR atudiaa of the paraaagnetic ions Ni/NH3/6 T and Co/NH_/ 2* reveal a discontinuous change in •/"H/ii " energy levels at ~ die zero splitting or Spin en_.g, v_v T. . coaplax aniona NO^'.dO^1", BF^1". PFg1" and at T /e for the spherically ayaaatric aniona Cl1", Br1" and I1 , 2. NKR relaxation in diaaagnatlc aaaonlacataa points to • aotion of the aaaonla aoleculea within tiia coaplex ions and

~~to extensive tuabllng vibrations of tha Cd/NH3/6 ion ae a whole.~~

Tha presence of two phaee transitions tj'/ and TJ'^ for SO^F points to covalant interionlc lntaractiona In eaaonla- cataa with eoaplex aniona. 3. Raaan and NHR atudiea ahow a change in ayaatery or splitting of the elgenvlbratlona of tha coaplex aniona and

Changs in vibration aysaetry of tha M<3 aoleculee in the region e of Tc' /. *. X-ray atudiaa prove tha low-teaperatura phaae of the aaaonlacatea td ba aonocllnlcwith a specific voluaa eaaller than'that of the high-teaparatura cubic phaae. Tha dacraaae In voluse la tha graetea for HOj1" and tha leaat for I1", and la proportional to the taaperatura of the phaae transition.

f •..I B511 B512 Is Triplet atata DI of T4«|> emtei ta CaOll* , W.Tb. Uwckebech and M.J. fouli. I. RmdnioD, C. McBonagh, Ihyiiul. Laboratory, KaeetUngh Ouaea Uboratotluai der liikiunlTereileir lallia Trinity Collaia, Dublin 1, Ireland. poettue 9M«, ]M0 «* Uldeu, The lethorleudi. r. Danon, nqpilet Dentrcaant, Unltrerfitr o« lull, Hull. Inflatta Ite performed nuclear-nuclear doubla raaonanca naarjreaante (HUHOOIt). aaide fKO«° nuclear esin-lattiea relaxation •eaeureaemti, in order ta inveetigate the thanal eoutaeta between opin eyeteaa in paraaagne'tic eingle eryetal^l. la CaOiMg fA(Hi) eantru eonalating of tin alaeeteoa In our aaanlei of deutoratad copper-caaeiun Tutcoa Mlt (Cu,Zn) Cf2 <5O4)2* trapped in aa anion TMaoey, ona of tha norael nellbboatios 6(HtD)2 0t it appeared poilible to aeaaura directly tha chanal contact between 1 tba deuterono end tbe pretona lit cha watort of hydracien. Title ii carried out C* * inn of which la replaced by Kg", ara obaanaa onbia- experlawitaUy in an PHX epactroeeter with Q-oeter detection. We fine etrongly quent to nautnii irradiation. Thaaa cantraa ahaorb li|nt aaturata tha ^ aplna and inwdiattly af taiwarda m osi*rra ttia i:!ian|« in •crongly in tha u.w.' apactruai and glv* riaa to s loaf-lived 1 tha '& aifnal and tha ralaution of thia aignal to iti itationafy yalua. red phoiphoraacanca . 0.D.M.I, ahowa clearly that the phoa- Aa tha aantionad contact batvaao tha dautaroq Zaoan ayatm and tlta pnoraacanea originate! in a apin triplet Mete of a cantrrwitb procon Zaaaas ayatam takaa placa via tha dipola*dipala intaraceion ayvtaia of tetragonal ayaaatry. The tatraeonal axia colncldoa with the

th«-alactrena (Cu*- iom)f M can colltec infonation vith.thia doubl* Taao- vacancy - iapurlty axia (i.a. a crystal [100] dlraction). Tba nanea taehniqua, about tha oatura of the thanal contact batman tha proton O.D.H.I. sfraetrua fita tha apin neeiltonian. Zuaan ayium (KS) and tha alaetron dipola-dipola ayitaa (EDD5). On tha I-I • »(«." - J8(>" • * 1.1 otbar hand «• alraady hava a larga nuafaar of axparinttntal data about thia charaal contact at our diapoaal* fcott tha proton relaxation aaaauraaadta in with S - I, I - 5/2. (,, - 1.999, tK -1.991, S • 49.1 as and tha ebova-MBtiOMd auplai [ ll. Thaia axparinanta could ba explained uith A,, • 1.96 el. Tha intimity of tha h.f. trimltlona •horn that a cneory baaed on tha eo-callad thraa-apin procan (alaetrott-alaetron-proton the interacting nucleua ie ^^ (flr Hhich th« ieotoaie akgnleace flip) u the s»chani» Dahind tht charaal contact betvatn tha PIS and the la 101. ' DOS 111.. Obaarntion of tha r cantra 171 worn detecting the I tfith coapleejaotary data about tha ao-called croat*rila]Mtien between the A cutra phoaphoraacance and vica-varaa appura to be conalltant SOOS and tlw electron Zeanan ayatflaa [31 and about tha altctmn apin-lattica with ideaa of anargy tranafar between f end P^ cantrf• at low relaxation tim [41 we will give a quantitative description of Che behaviour temperature. of tha thanal contact between the KS and tha 1DDS. 1. L.S. Welch, A.8. Bughaa, G. Pelli and A. Schoeniarg, J. la Phyii<|ua Colloque CJ, lupp.I2, 17, 191, (1976) 2. F. Edel, C. Benniei, T. Marie d'Auhignl, t. leaaiteia and [ll J. nn Houtan, V.Th. Henckebach end H.J. Foulia, Fhyiica 92 • (1977) 201. T. Twarowiki, Phyi. Uv. Lett. 2B, 1261, (1972). [21 J.. wan Ronten, U.Th. ttinclubach and H.J. Ponlte. Fhyaica 92 > (1977) 210. (31 J. root, V.Th. Uaockebach and «.J. Foulia, Phylica, to be pobliihad. [41 A.C. d* Vroonn. Thalia, Lalden, to be published.

B513 ROHSJUILIBRItrU 29 am^-mOSOS BOmffiffiCK AES •I't'.f''.' 3PBCTHU, DIFFD3I0H IB OFTICALH PtTHPBD RUST mLaii Institut* for Th«or«tical Riyaica of of 8clenc«,Moscow,Oh«rnogolovlc«,W24J2,US3Il-

Iha crucial question in tha "bottlaneck" fhyaica isi vhat Cioetfsn giva contribution to tha phonon bandwidth £a tdaf i- niag tha noaliar of modaa "on spaaking tarns'* with the "spins". It is obvious that tha lisa width So gives contribution to £3 abut there exist aontimdloting opinions about the role of the phonos broadening "f * due to phonon reabsoiptios /l/. Aooordingto Anderson's srguaents based on quantum uncertainty, •f * gives no contribution to AU . Aocording'to Iownes,ai bandwidth &u narrower than the duping f * has no sense. We have developed a theory of the phonon bottleneck based on equations for nonaquilibrium Green funotlons. As is seen froa this theory,the above aentianed contradiction arises because people have in Bind the phonon field described in tern of aode occupation nuBbera,in which case £a can ba only the width iuv, ' giving the umber of excited nodes. In fact,the phonon field oust be described in tens of s(aq) ,the apeotnl density at frequency Co for the oode a, .How another bandwidth 4U sxijts,giving the range for since for larger f* sore nodes are excited bat to a lower level.

1. Anderson,P.f.,PhjaJ!eTr.,U4,1002(1959). C5U ' C512 . 4:5 MIGHT smrt juta NUCLEAR RELAXATION TDBS.OH MIORIBODS SPIN-LATTICE RELAXATION ID INTOtHrrAIiJTl*8 VjGa ADD V3SI Hi-P AMD CU-Hl-P JOLOXO A.P.STEPABOV. A.V.SKRIPOV and B.A.ALEXSABHIH, Institute of Metal Physics, Cral scientific Centre of'the USSR Academy I.BMOWTI. K.TGWA, Sn4 A.1OVAS, Central Raseuch Institute for Physics, H-1S2S Budapest. P.O.Box 49. of Sciences, Sverdlovsk 620219, USSR Hungary The temperature dependence of spin-lattice relaxation tlae, for 51., «!»„"Ga _an „.d, •"'G„a In VjGa and V3SI powders was studied X 1BE» TH tutfch Urn M •»% " ' A roon-tcnparatuxe nuclear magnetic resonance study Is reported in detail between Tc and 295K, In both compound* (T..T) ' lncreatM on two kinds of metallic glasses. The Knight shift (K) and the as the temperature is lowered* In the temperature range* 7O-295K 1 2 spin-lattice (T,) and spin-spin (T2) relaxation times of P for V36a and 9O-295K for V3Si (T,?)" ' there is a Xinewr depend- P x 27 nuclei were meaaured In electrodeposited "l1OO-x i[ l"* = > ence of lnT in accordance with Gor'kov's theory /I/. In the tem-

and rapidly quenched Cu6QNl24P16 amorphous alloys. The samples perature ranges 3O-6OK for V3Ga and 75-9OK for V3SI the temper- 1 were prepared from foils aud ribbons, respectively. The Knight ature dependence of (T^T)" flattens. For V3Si this feature corre- shift was measured by CV-NMR technique at frequencies 7.5 HH> lates with a sijoilar feature of magnetic susceptibility attrib- and 11.5 MX, and the relaxation times were obtained up to uted to the fine structure of electron energy spectrum /2/. An 36.4 HRz by using a Bruker SXP pulse spectrometer. The 'P NHR anomalous enhancement of spin-lattice relaxation rate near the

~~parameters hardly depend on phosphorus content in electrodepo- superconducting transition temperature, To, was observed for both~~

sited Hl-P alloys, in accordance with Schone and Gustafson's V3Ga and V3Si. Order parameter fluctuations above Tfi are believed results /I/, as compared to rapidly quenched OUo.s^dg.so'loo^x . to be responsible for this effect. Specific features of A-15 metallic glasses HI. As far as the Cu-Ni-P is concerned,' this structure compounds favouring the (T^T) enhancement are dis- is the first observation of NHR In this amorphous system. The cussed. Impurities are shown to destroy this anomaly. From exper- experimental results are analysed in. terms of the Korringa imental data an relaxation rate. Knight Bhift, quadrupole interrelation K^.T * const, and of the possible electronic struc- action and magnetic susceptibility, we determined the electron ture of lEhese metallic glasses. state density at thu Fermi level, N(E..), and contributions of Kf_. different d-subbands to the density of states. The results are

1. Schone,B.E. and Gustafson,P.A. Bull.APS 2j[, B27 (1976) compared to other experimental approaches and to band calculations from first principles. Disordering of V,Ga and Fe substitu- 2. Hlnes.N.A., Kabacoff.Ii.T., Kasegawa.R. and Duvez.F. In 1 tion for V in V3S1 are shown to reduce (T^)" and to weaken Its Amorphous Magnetism II, Ed. Levy and Hasegava, Plenum, temperature dependence due to N(Ef) reduction. Mew York, 1977, p.594.

~~1. Gor'koVfL.P. and Dorokhov.O.N. J. Low Temp, Phys. 22, 1 (1976). 2. Pan.V.M., Shevchenko,A.D., Prokhorov,V.G. and Harchanko,V.A. Pis'ma Zh. Heap. Teor. Fiz. 25, 141 (1977) .~~

C513 COHDUCIION ELECTRON SPIN RESONANCE AND RELAXATION OF BIMETALLIC SAMPLES B.VICODBQUX.J.C.GOUBDOH.P.FRETIER and J.PESCIA. Laboratoire de Kagn^cisme et d'Electronique quantique, Faculte deg Sciences. 39 Allees Jules CUESDE 31077 TOULOUSE

Since Che first experiments on conduction electron spin resonance, Dyson made che assumption that surface relaxation had to be taken into account /I/. He IV offered to determine this effect by means of a phenomenologicaL probability c. Surface relaxation results in a broadening of the resonance lines, che broadening being inversely proportional to the thickness of samples, few meaiurements of c have been carried out on lithium and sodiun. Results differ somewhat with the authors, due to che limited surface effect in these samples (e ranging from I0"6 co I0~7). A much greater broadening was observed by Janossy and Honod HI, with aluminum »labs coated with zinc. In their interpretation, they asked the question whether bulk relaxation within the zinc had to be taken into account. Such a possibility has been investigated by other authors IV. They introduced in the boundary conditions appropriate terns describing the coupling between magnetizations •f the cm metals; these tjrms were superimposed to those describing surface relaxation of fflecals alone. However, che problem whether magnetization coupling at the interface has to be taken into account in all cases has not been solved so far. In order to solvt iC, we have undertaken a systematic study of bimetallic' interfaces. Samples wer> prepared by thermal evaporation in a I0"& torr vacuum system. Cesr spectra were obtaiaed from Li/He samples (He being Sb, Bi or Cu). A series of samples have been used, with He thicknesses ranging from 0 to 2000 & and lithium thicknesses

(dLi) ringing from 0.5 to 10 ym. With Sb and Bi the broadening is in agreement with Walker's model of surface relaxation /A/. The coupling between metals is negligible, the lines are Dysontan, the Hnewidths are proportional to d£{ and c is typically I0"4 and independent of temperature. Direct —-jurement of Tj by the modulation method /5/ shows that surface relaxation has a longitudinal as well as transversal character. Kith copper, anomalous features are brought out: che lines are no longer Dyionian and the broadening is proportional Co d£i« One interpretation would be the coupling between magnetisations of Li and Cu, and another would . be that assumptions made in Walker's model of surface relaxation are no longer valid for Li/Cu samples.^Analyical simulations of lineshapes are needed to conclude. 1. DTSOK P.J.,Phys.Eev.98 (1955) 349 2. JAHOSSY A:,MDSOD P., J.Phys.F 2 (1973) 17S2 3- FLESHER L.D.,FREDKIH D.R..SCHULTZ S., Sol.St.Comn.1B (1976) 207 4. HALKEB. H.B.,Fhys.Rev.B 2 (1971) 30 ", 5. VICOUBmnt B.,COUHMH J.C, PHSCU J.,J.Phys.P£ (1976) t575

?.•'{•• Veinger, A.I. B1513 Windsch. W. D511 D512 BK0H1HCI& 1B- 1'o, ^\ IBB cBanojo. SHOW wo SSBDCHJBBS or OSSUOUBCDRZ COBOOISS. EHI1TS OF renKCOORDHUTEDPHOSPBOPD S CCMP0UB1JS in SPUIU KTRCXS n JUKXL, AIMI, VTJHL UD iBWUIC KSHOUBY BKBIYAIITBS- B.I.Ionin. T.I.ZacBiator, G.i.Borkora, V.Ta-Eomaror and A.i.Potror, Leningrad Lensoriet Institute of Technology, Yu.A.uSTTmTOK.Yu.l.STBBLBgQ. Tu.K.GSIHHIB, D.H.KHAYTSOT a&d Leningrad 198013, UEBB m.A.TOHOsOV. 1KB Laboratory, Department of Chemistry, Mosoow 1 1 State University, Moscow 117234, U3SH, BUB % spectra parmeters, ' P and 'o chemical shifts, tha ralnes of E-B, H-P, H-C ssd other coupling constants and their 193 Bg HE spactr* of mom than 60 compounds HjHg (I) and signs have been determined for a variety of foureoordlnated 199 BBgX (II) In various solvents have boon studied. the Hg chemi- IbosphoxuB coapounda (phosphonatesi thAonphoaphonatas and others). cal shift ranges are approximately 1000 ppa for (I) and approxi- Iha conformation of molecules related to C-C, C-P and P-0 bonds - mately 1500 ppm for (II) and depend strongly on the structure of hare been aatlxated with the aid of lantanlde shift reagents B, substituents prsaant in B. Structure factors an sore Impor- (LSR). Tha I£R influence on 31P and 13C shifts as well as eon- tant than aolTent affacta which Bay amount to 100-150 ppa.In sub- tact and pseudocontact contributions to lantanida shifts have stitutsd arylaarsury derlTatiTes (XC^H^gBg eleatran donor sub- been evaluated. atitaanta such as (CRjjjS, CBjO, OBj shift the signals to the lo- She variation of IQK paraaetexa was partially attributed to wer field wbsrea* electron withdrawing ones Induce npflald shifts tha contribution of phosphorus 3d orbitalB Into transmission of whloh Is indioatlTe of dominatlTS role of paramagnetic contribu- spin Information* tiona. In bansylawicurlo haUdea (OHjln^Hj^Hgl. nata- and para- Valuea of coupling constants VQP depend on variation of a 193 •athyl groups causa only Insignificant changes In Bg shielding character of carbon and phosphorus orbltales in tha direction (1-3ppn) while ortho-netojl aubstituonta shift the signal auoeaa- of C-P bond; 143.9 Hi for CHjP(O)(oSt)%, 195.8 Hi for oiToly by 25 and 50 ppn to the lower field. It is due to inoraase 1 ke20.0=CHP(0)(0Me)2, 300.7 BE for CB?CSCF(0){0lla)2. Jcp and in populations of oonf otaars with easily polariiaole 0 - Eg bond 2jH0P e°uPUngs varies significantly froa phoaphonates to lying in the nodal plane of K-orbltals: and participating effec- thionphosphoiintas, the aora alactronegstlve substituenta ^at tlTely is hyparconjugation with the r-uyoteri. jh==jiuras t;> ion values of the Constanta haying been observed, Ihe •leetronis and spatial effect e In organomereury darlTati- fi lor example, iOr XsO and I=S the following values o't ^Jgp and TO» of tha oyelohazana, allyl, Tinyl, and acetjlana series and 2 JHCP have been obaarredi CBjFCUOlg 104.}, 81.2 and -16.8, thedr lnfluenct on 199Bg onoaicai ahlfto ara analysed. Iha poasi- -14-3 H«i PhCH=CHP(I)Ue2 98.2, 80.6 and +24.1, +23-3 Hi; ollity of tha use of 19'Hg DE spectra In studios of optical lso- PhCH=CHP(I)012 154-3, 115.3 and •34.0, +28.0 Be. The similar a»re is diacuaaod. S results have been obtained for 'cgp and 'JHCOE couplings. In the Beries of (Me^R)xFX oarivatlvav valaea of Jjjjj(jp vere smoothly increased from 1=0 (+9.5) to I=E (+11.0), X=So (+11.8) and Isle (+12.0 Bs). The significant variation of Jp. and J» couplings (up to 26 Bx) was eBtimated for phosphonated involved In coordination with ISR.

~~D513~~

~~COUPLINGS IS METBVLTIN HALIDES~~

V.S.PETROSVM). A.B.PEHMIN, o.A.REOTOV, chemistry Depart- ment, Moscow State University, Moscow 117234, USSR. J.D.ROBERTS, Gates and Crellin Laboratories of Chemistry, • California Institute of Technology, Pasadena, Ca 91125, USA.

It has been shown previously /I/ that there is a linear correlation between 1J(13c-199Hg) and 7.-('!a-199Rgl for diben- zylmercury in various solvents, which supijrted the conclusion IV that electronic factors are responsible for the changes In C- 99Bg and 1H-199Hg couplings on solvation of organonercury compounds• In this study it was shown that 1J(1Jc-119Sn) for methyltin halides Ke^SnHal^ (n = 1-3; Hal =Jl,Br) in various solvents

(CC14, benzene, nitrobenzene, CD^CH, (CD3)2CO, and DMF-d.) Increase proportionally, but nonlinearly, to the growth.in 2J(1H- 19Sn). These results suggest that besides the Fermi contact term other contributions are important for 13C-119Sn couplings and first of all the spin-orbital term. Different behaviour of 1J(13C-199Hg) and 1J(13c-119Sn) can he explained in torms of different s-character of C-Hg (501) and C-Sn (251) bonds.

~~1. V.S.Petrosyan, J.D.Roberts, org. Magn. Res., 9, 555 (1977). 2. V.S.Petxosyan, O.A.Rautov, Pure Appl. Cham., 37, 1i7 (1974) 1 J. Oxganometal. chem., 76, 133 (1974).~~

~~I I fL;-1 AUTHOR INDEX~~

~~Abaghian, 6.V. A34O6 Anokhina, L.K. B4312 vj Abdrahmanov, R. C2311 Antipin, A.A. B1603 fj Abdraschitova, N.A. A2311 Antokolskit, G.L. B13O4 1~~

Abdrashitova, E.I. C2313 Antsiferova, L. B33O8 $t Abdulsabirov, R.U. B2323, B2345 Anufriev, V.G. C34O1 % Ablart, G. B2333, C423 Archipov, S.M. B1612 s| Ablov; A.V. A4311 Arohipov, V. D33O4 & Abragam, A. B211 Ardelean, I. B43O4 I Abramov,. A.F. D4419 ' Arend, H. C113, A23O8, i| 55;) Abramenko, E.L. D23O6 C33O7 3 Ackermann, K. C411 Arends, B. D33O1 ;;| Afanasiev, V.A. D1413 Aronov, A.G. A321 -| Ahola, H. C4316 Arribart, H. C414 1 Ahonen, X. D422 Arro, I. D4416 /J Ailion, D.C. A23O5, C313, Arseniev, A.S. D114, D1413 | A511 Artyukh, R.I. D1305 1 Ainbinder, N. A4314, A4315 Asisov, E. A422 ' I Aksenov, D. C43O9 Astapov, B.A. D44O1 -\ Aksyonov, S.I. D213, D214 Ataev, A. D25O3 11 Albanov, A.I. D421 Atsarkin, V.A. 122, B222 i Aleksandrova, I.P. C2312, A4319 Auch, W. A33O1 i\ Aleksashln, B.A. C512 Aue, W.P. 115 fi Alekseev, A.V. B114 Avarmaa, R. A3 303 \\ Alekseev, B.F. B2344 Avdeenko, A.A. A33O8 ^\ Alexandrov, E.B. D43O8 Awakumov, E.G. B43O2 si Alexandrova, T.A. D23O1 Azzoni, C.B. B2331 \\ Aliev, Sh.H. B4312 Alirabek, B. D4313 Babushkina, T.A. B43O5 : Allzon, J. C421 Bachmann, P. 115 '.h Alia, M. A112, A13O3, Bacquet, G. A2325, B233O % \i A1311, D2509 Baczkowski, A. D1403 1 Alma, N.C.M. D122 Badalyan, V.G. B2327 -§i Al-Mowall, A.H. B2343 Bagraev, N.T. A322 ^ von Alpen, D. A23O7 Baican, R. D2304, C3312 ^ Alsem, H. A2327 Baisa, D.F. D34O6, A4313 J Al'tshuler, S.A. B113, B212 Bakai, A.S. C1310 ^ Altshuler, T.S. C4311 Baker, J.M. B213, C43O6 % Altukhov, P.D. A323 Bakonyi, I. C511 % Alymov, I.M. A423 Balanescu, M. C33O8 -| Amanis, I. B15O5 Balcerowicz, D. A3412 | 1 Aninov, L.K. B2324 Balcerowicz, K. A3412 ^ y.- Anlnova, R.M. D44O3 Balcou, Y. D431O -* Amirkhanov, Kh.I. B4312 It Balicheva, T. A422 2 Anders, A.6. C14O8 Baran, H. B1604 | Andersson, L.O. A2325, B2316 Baranov, P.G. B1520 } Andrew, E.R. 141 Baranov, V.S. -B13O4 % Andrianov, V.A. B43O7 Baranowski, J. B2325 J Andrlessen, J. B33O9 Bargon, J. 133 ; Andronenko, S.I. B2314 Barklie, R.C. B15O9, B1510 ': Anlkolenko, V.A. A3 404 Barlev, A.A. A341O Anislmov, A.N. C33O6 Barta, C. C23O7

If" 1 m Baryakhtar, V.G. C212, C34O5 Bondar, A.V. A4313 Bashkirov, Sh.Sh. B413 Borcard, B. 01411 H; '' k' 'AT Basosl, R. D1410 von Borczyskowski, C. A421 Bates, A.R. A513 Borer, A. . A331O ST^ Bates, C.A. B122 Borodin, P.M. D34O3 K'f •-" i Baturin, S.M. D23O5 Bproske,'E. A421 m Batyuk, V.A. D323 Borovlk, A.E. C1401 Becker, K.D. A2317 Borovlk-Romanov, A.S. C123, C33O2 Belak, J. B2319 Borshch, S.A. B43O9 Bellnskll, M.I. A4311 Boscalno, R. B221, B421 Belobrova, I.A. A4319 Bottcher, R. B331O Belonogov, A.M. B2344 Bottomley, P.A. 141 si Belostozkaya, I.S. A3 407 Bouffard, V. 111 if Belov, K.P. C14O9 Bourdel, D. B2333, C423 ft; Belozerskii, G.N. B411, B43O1, Bouthinon, M. C3311 ¥&• B43O2, B43O3 Bouysset, C. B233O :§.-•: Benderskli, V.A. B314 Bowman, M.K. C412 Bene, G.J. D1411 Bratunets, A.G. A2313 ^. Benner, H. C34O4 BrSuer, A. B331O van der Bent, S.J. A33O2 Bredlkhln, S. B1525

SL'r . Bexestova, S.S. D441O Breltschwerdt, K.G. D25O8 Berglund, B. A23O4 Brick, A. B232O, B312 Berlin, G.O. C34O7 Brinkmann, D. A23O7, A23O8 Berkova, G.A. D512 Brookeman, J.R. A43O4 Bersuker,. I.E. B121 Brun, E. 143 Berthet, G. C421 Brunner, W. C23O8 - ' Berzhansky, V.N. C34O3 Bryukhova, E.V. A43O8 -i j/ : .1" - Besobchuk, V. B232O Bubnov, N.N. A34O7 s. Betenekova, T. B2341 Buchachenko, A.L. A2323, A313 Bezrukov, O.F. D313, D3313 Bugai, A.A. B14O4 Bhattacharyya, B.D. B14O5 Bulanly, M. B1524 i Blblcu, I. B43O4 Bunbury, B.A.P. B43O8 Blernackl, S.W. B14O3 Bunkov, Yu.M. C121 f 'it- Bljvank, E.J. B33O9 Burg, J. C14O2, C14O3 'r' Bltenbaev, M. D23O3 Burlakova, E.B. D13O7 % Blanc, J.P. C421 Burshtein, A.I. D311 Bleaney, B. 123 Burzo, E. C33O8, C3312, Bllcharskl, J.S. A14O7 B43O4 Bllnc, R. 101, C23O4 Buslaev, Yu.A. D25O4, D25O7 Bloom, M. D223 Buttler, W. C411 Blumenfeld, A.L. D34O7 Buzare, J.Y. B16O2, B214

!;•'; Bock, E. D34O1 I Boes'lger, P. 143 Cantor, R. 121 t- Bogachev, J.V. B2344 Carlsson, 0. D111 |; Bogachev, Yu.S. D441O Casella, L. - B2335 f: Bogdan, M. A2326 Cevc, G. C23O4 Bogdanov, P.V. B412 Cove, P. C23O4 Bogdanova, Kh.G. C312 Chabibullin, B.M. C4315 Bogomolova, L.D. B2315 Charnaja, E.V. B13O3 Bonn, H.G. A2329 Chatterjee, R. B23O7 Bokov, V.A. C14O5 Chelkowski, A. C4317 :::' Boldeschool, A. D24O1 Chen, T. (Dschen) A34O2 Boldyrev, V.V. B43O2 Chepeleva, I.V. B2336 Boinmel, H.E. B112 Cheremnykh, P. D432O

II Cherenda, N. B15O4 Dotsenko, G.I. A13O9 Cherknsov, B.I. A2315 Dovator, N.A. C25O1 '<• Cherkasov, F.G. C4313 Drapkin, V.Z. B2344 -••;:• Chernyi, A.S. B16O9 Drulis, H. C431O •- Chernyi, V.D. B1S21 Dubbers, D. C411 *' Cherpak, N.T. C33O4 Dubinsky, A.A. D43O5 ) 'V-' Chesnokov, E.D. D34O6 Dudich, I.V. D13O4 ; Chile, J. C3311 Duglav, A.V. B113 '?ir 1 Chipara, H. D23O4 Dumesh, B.S. cm 1 -' :; B2342 Dupanloup, A. 1 Chirkov, A. 1 Chizhik, V.I. D33O9 Durand, P. C421 |lS 1 Chiystov, A. B23O2 Dushkih, A.V. I35,'A314 |f- Chobanu, M.P. B23O4 van Duyneveldt, A.K. C112' , 1* > 04408 Cholakh, S. B2341 Dvoryantseva, G.G^ il':i •• Chugunova, G.P. B4313 Dyckes, D.F. D113 ' afi -. Ciccarello, I. B223 Dzibmko, V.M. D25O3 Clarke, R.H. A33O4 Dzuba, S.A. B3317 "$ ' Clement, S. C423 '4 Clerjaud, B. B44O5 Ebert, B. D43O7 % Conover, W.H. D113 Egemberdiev, Zh. B15O7 Corradi, G. B1511 Ehnholm, G.J. C4316 |ji * Cozar, O. B23O3 Eichhoff, U. D312 tB Cukierda, T. B2325 Elman, B.S. B3316 Emiryan, L.M. C33O6 ! Dadali, A.A. D23O1 English, A.D. . A213 i Dally, E. D33O5 Eremenko, S. D13O3 Dalrymple, D.L. D113 Eremenko, V.V. C114, C122, i: J Dalton, L.R. D13O2, D414- C14O6 r Dam, J. B33O9 Eremin, M.V. B1518, B23O8 Damadian, R. A223 Eriomin, V.A. D24O4 Danllov, A. A43O2 Ermolaeva, T.T. D33O9 1 ' Danllov, V.V. C33O3 Ernst, R.R. 115 k Darabont, Al. B2337 Erofesv, L.N. A212 is Daragan, V.A. D3317 Ershov, B. D44O7 'Wl" \ -Daraselia, D.H. D331O Ershov, G.H. C24O2 ' Dautov, R.A. A13O4, D14O9 Ershov, V.V, A34O7 ?;." Davidovich, R.L. B14O2 Esakov, S. D44O7 "j£ if: Davis, J.H. D223 Evelhoch, J.L. D111 ; •af Dawson, P. B512 Deigen, H.F. A2328, B234O, Fainzil'berg, A.A. D4414 B323 Fainzil'berg, V.E. A4311 Denlsov, G.S. D33O8 Falaleev, O.V. A23O2 a W Denker, B.I. B1501 Falin, H.L. B3316 ''?' Depireux, J. A232O Farca;, S.I. B2337 '•ti it' Descents, P. C43O4 Fayet, J.C. B16O2, B214, Dikanov, S.A. B33O5 B2311 f Dinse, K.P. A414 Fechner, E. A2324 Dmitrisv, S.P. C25O2 Fedii, A.A. B16O3

Dobryakov, S.N. A3 409 Fedln, E.I. D34O7, D44O8, • ';/- Doerr, K. C411 154 .,]: Dolgopolov, D.G. C43O1 Fedin, S.G. B2344 '',*• Dong, R.Y. D34O1 Fedirko, V. C34O6 .Donskaja, I. B16O5 Fedotov, V.D. A2311 Doskofillova, D. 142 Fedotov, V.H. B3315

III Fedotov, Yu. B232O Goldacker, W. A413 Fedutin, D.N. C422 Goldanskii, V.I. D24O7, B43O6 | Fel'dman, E.B. A211 Goldman, M. B211 Ferretti, J.A. D1401 Goldsmith, M. A223 Feshin, V.P. D44O5 Golenishchev.-Kutuzov, V.A. B111, B1301, Filatov, A.V. D213, D214 C312 Fischer, K.J. A2329 Golovchenko, L.S. A43O5 Fleisher, V.G. 144 Goloytsov, N.I. D4417 Fogel, V.Ri D121 Golubev, N.S. D33O8 Follstaedt, D.M. A23O6 Gorbachevskii, S. B411 Fomichev, A.A. D4417 Gorbunova, N.P. D13O5 Frankevich, E.L. 134, A33O5 Gordon, A.Ja. A4313 Freeman, R. D412 Gordon, E.B. D43O4 Fretier, P. C513 Gourdon, J.C. C513 Freudenreich, W. A23O7, A23O8 Grachev, V.G. B3314 Fujara, F. C411 Grande, S. D321 Fukushima, E. C23O2 Grant, D.M. A1310 Grazhulis, V.A. B1517 Gabuda, S.P. A2319, A2321 Green, E. A43O9 Gachegov, Yu. A43O2 Grechishkin, V. B2313, A422, ' Gaevoy, V. D2401 A43O3 Gaggelli, E. D1410 Grechishkina, R. B2313 Gaidai, Yu.A. C13O2 Grekhov, A.M. B2326 Galkin, A.A. C211, C212 Gribanov, A.V. D341O Galland, J.P. B44O5 Gribova, Z.P. D13O6 Galilee, J. C421 Griffin, R.G. A114, D222 Galushko, V.A. C211 Grimmer, A.-R. A221, A2324, Garifullin, I.A. C431O D44O4 Garifullina, R.L. B2345 Grinberg, O.Ya. D4305 Gataullin, 0. B2328 Grishin, Yu.A. 135, A314 Gavrilov, F.F. B2339, B2341 Grishin, Yu.K. D4412, D511 Gaysin, N. D33O4 Grobet, p. C14O2, C14O3 Gehlhoff, W. B1515, B16O6 Grochulski, T. A4312 Geifman, I.N. E234O Gromovoi, Yu.S. B1511 Gelardi, F.H. B421 Grdssxsann, G. D44O9 Gel"fman, M. A4321 Grunder, W. A512 Gelineau, A. B44O5 Grupp, H. C411 Gendel, L.Ya. D24O5 Gubanov, V.A. A43O7 Gershenzon, Yu.M. D4318 Guilotti, M. B2335 Geratein, B.C. A111, A13O8 Gumerov, F. B1605 Geschke, D. D33O6 Gunsser, W. B43O3 Gilmanov, A.N. A231O Giinthard, Hs.H. D13O8, A3402, Gilyazitdinov, D.G. B33O2 B311 Giordano, M. B33O3 Gurevich, A.G. C33O6 Gitsovich, V.N. B43O1, B4302 Gurevich, A.Z. D1413 Giurgiu, L. B2334 Gurinovich, G.P. A33O9 Glasbeek, M. B1401 Guskos, N. B1610 Glazkov, Yu.V. D25O5 Gustavsson, H. D331O Glinchuk, M.D. B234O Gutowska, M. B16O4 Glozman, E.A. C1407 Gutowski, M. C222 Glumov, A. B2313 Gutowsky, H.S. D221 Godlewski, M. B15O6 Guttler, W. A33O1 Godovikov, S.K. B412 Gold, D.G. 131

IV X Haavasoja, T. 152 Il'yasov, A.V. D25O6, A341O Haberkorn, R.A. A114, 13222 Ingman, L.P. A14O2 i-ji Habuda, S.P. D14O5, D14O6 Inners, R.R. 0113 Hackeloer, H.J. A2327 loffe, V.A. B2314 Haeberlen, U. 114 Iolin, E.M. B13O4 Hagen, H. C113, IC214, Ionin, B.I. DS12 C33O7 Irisova, N.A. D413 Hahn, E.L. 131 Ishchenko, S.S. B312, B323 Haken, H. A23O9 Islander, S.T. C4316 Hakli, H. D422 Ivanov, Ju.N. A211 Haldre, I). B15O7, B2341 Ivanov, O.V. D25O3 Halstead, G.W. C23O2 I-.- ov, V.I. C34O3 Haraldson, S. C33O9 Ivanova, A. B33O8 Harina, B.J. D113 Ivanova, S.V. C212 den Hartog, H.W. B33O9 Ivanova, T. C2311 von Hartrott, M. A43O6 Ivanova, V.I. C33O4 Harutunyan, W.Z. B2312 Ivashchenko, A.N. C14O4 Hashimoto, T. C34O2 Ivin, V. C43O9 Haubenrexsser, a. A221 Iwasaki, H. B33O7 A43O2 *--* --'- Hausser, K.H. A413 Izmest'ev, I. Havrichkov, S.A. C34O3 Hayes, C.E. A23O5 Jacquinot, J.F. B211, B33O6 Hayes, W. 125 Jaek, I. B15O2 van Hecke, P. C413 Jakes, J. 142 Heinmaa, I. A112, D34O9 Jannek, H.-O. A2318 Heitjans, P. C411 Janssens, G. C413 Hemmes, P. D211, D212 Jarosik, H. B321 Hemminga, M.A. D122 J^dryka, E. C222 Hempel, G. A13O5 Jeener, J. US - Henderson, B. B15O9,, B1510, Jezierska, 3. B231O B512 Jezierski, A. B231O Henner, E.K. B2315,. B422 Jezowska-Tr zebiatovska , B. B231O, B2325, Herrick, R. B321 D2S01 Herzfeld, j. D222 Johnson, L.F. D113 Highe, A.J. A122 Jokisaari, J. D44O6 Hilbrants, W. C43O? de Jong, H.J. B1401 Hiltbrand, E. D141 • Jordan, F. D211 Hinshaw, W.S. 141 JSrin, E. D13O8 Hobart, D.R. A33O4 Jotikov, V.6. C123, C33O2 Hoehener, A. 115 Juhar, J. B2319 Hoehne, j. A43O6 Jurga, K. A232O HShne, M. B1514 Jurga, S. A232O Holland, G.N. 141 Houlier, B. C23O3 Kabachnik, H.I. A34O7 van Houten, J. B511 Kaburin, N. D4317 Hronsky, V. B2319 Kaczmarska, K. C4317 Hull, W.E. * D312 Kalabin, 6.A. D4413 Kalabuchova, F.N. B1611 Ianculovici, B. D4315 Kalamkarov, G.R. D24O7 Ibragimov, Sh. B431O, C43O9 Kalantarian, V.P. C43O3 Idzlak, S. A131Z Kalashnikov, V.P. C33O5 Ievskaya, N. D43i; Kalenik, J. A43O9 Ignatchenko, V.A. C14O7, C221 Kalibabchuck, N. D24O1 Ikegaml, T. C34O2 Kamenev, V.I. C212

V K Kamienska-Trela, K. D44O2 Kochelaev, B.I. B113, B322 Kaminskaya, E.P. B43O7 Kodeas, B.N. C43O5 ;' Rammer, H. C213, C323 Kocrblein, A. C411 Kamzin, A.S. C14O5 Kojima, Y. C34O2 Kanert, 0. A2327 Kokorin, A.I. D24O5, D24O8, Kang, S.-Y. D221 A34O8 Kaplyanskii, A. A. C23O7 Kolomiecs, I.A. C25O4 Kaptein, R. A314, A411 KoXoskova, N.G. B322 Kararhevtsev, V.A. A33O8 Kolovrat, J. C331O Karlicek, R.F., Jr. D43O2 Kolpakova, L.N. C33O4 Karnachev, A.S. C34O5 Koltsov, A.I. D341O Kasakov, M. B43O3 Komarov, A.V. C25O3 Kashaev, R.S.-H. A231O Komarov, V.Ya. D512 Katila, T. B43O6 Komashnja, V.L. B13O3 Kats, L.I. B44O3 Konchitc, A.A. B3311 Katyshev, A.N. D4322 Kondakov, V.I. D114 Kazar, D. B2319 Konopka, D. C4317 Kerlin, A.L. A2312 Konovalov, V.I. B323 Kessel, A.R. C312, C34O7 Konstantinov, V.N. B2321 Kessenikh, A.V. D25O3 Konstantinov, Yu.S. D4312 1 Kessler, Yu.H. D3311 Kooyman, R.P.H. D33O3 Kevan, L. B33O7, C412 Koppel, I. B44O6 Khabakhpashev, M.A. C314 Kopvillem, U.Kh. B114' Khalmovich, E.P. B1301, B13O5 Koroblyeva, S.L. B16O3 T Khalilov, L.M. D24O2 Koreneva, L.G. D123 Kharakhash'yan, E.G. C321, C4313 Kormer, V.A. D23O6 Khasanov, A.Kh. B113 Korneev, V.R. C223 Khatchaturov, A.S. D23O6 Kornienko, L.S. B1501 Khazanovich, T.N. A13O6, A14O3, Korolev, V.D. B23O5 D3317 KoBhelev, O.G. B44O2 Khimich, Yu.P. B43O1 Kosov, A.A. B322, C43O7 Khlopin, V.P. B121 Kotelnikov, A.I. D121 Khrapov, V.V. B43O5 Kotkln, A. D4317 Khysainov, Kh. D33O4 Kotyuzhanskii, B.Ya. ' C13O5 Kibrik, G. A4315 Kovalenko, A. B1524 Kicelnik, V. D33O7 Kovarskii, A.L. D23O1 Kiese, G. C411 Kovtun, N.M. C34O5 Kim, A. A4314 Kozhanov, V.N. C43O8 Kimmich, R. D24O3 Kozhukhar, A.Yu. B16O7 Kimtys, L.L. D3411 Kozin, M.G. B412 Kirakosyan, G.A. D25O4 Kozlov, V.V. B13O4 Kirchmayr, R. A331O Koelowski, H. D1412 Kirillov, S.T. . B314 Kozyrev, B. B16O5 Kjuntsel, I. A4315 Krainik, N.N. C311 Kliava, J. B15O5 Kravchenko, E. A4321 Klimes, N. D43O9, D4319 Kravtsov, D.N. D511 Klimko, G. A3 307 Kravtsov, D.N. • A43O5 Klinshpont, E.R. B33O2 Kreines, N.h. C123, C33O2 Klochko, A.V. C114, C14O6 Kreissl, J. B16O6 Kobets, M.I. B16O9 Kriger, Yu.G. A2321 Kobychev, V.B. _D44O5 Krishnan, V.G. B14O6, B14O7 Koch, F. B15O8 Krlvenko, V.G. C14O4 Koch, R. B414 Krivoruchko, V.N. C13J)9 Koeharyan, K.N. B2312 Kropatcheva, E.N. D23O6

VI Kropman, D. B1516 . Lesin, V.I. Krulikovsky, B.K. B234O tetowski, St. 01403 .; Krutikov, V.F. B1518 Levinson, Y.B. BSI3 ; Krygin, i.M. B2323 Leva, C.J. D14O3 ' Krygowska-Doniec, M. B2332 .Lewis, J. 03401 Ksandopulo, G.I. A34O1 Lesina, V.P. 01401, 01404 Kukovitskii, E.F. C4311 Liachovich, V. 01303 Kulagina, T. B33OS Libennon, A.B. B413 Kulakova, A.M. D14O7 Liidja, G. A3311 Kulbatskii, V.P. C211 Likhtenstein, G.I. Dili, 01402, , i •Kuleshov, V.S. C1401 ' 01404 I Kulikov, A.V. D121 - Lindman, B. 03310 J Kundla, E. A112, A13O3, Lippmaa, E. A113, A1311, i A13O7 D34OI Kurashkin, L.V. B43O1 Litovchenko, A. A433O : Kuriata, J. B1610, A3412 Litvinova, L.V. 03311 Kurkin, I.N. B212 Livanova, L.o. B234B Kuropteva, Z.V. D13O9 Livshitt, V.A. 01301 0 Kurze, W. D33O6 Livehitz, B.L. D431I* Kusohenko, V.V. D3319 Losche, A. 0331, Hi

% Kushnarev, D.F. D4413 Loaovik, Yu.E. B44O4 Kushnir, A. B1524 Lott, K. B1S1B Kustov, V.E. .B14O4 Lounaamaa, O.V. B33O« Kuts, V.S. D331S Lovas, A. C511 Kutter, W. B2343 Lowe, I.J. D43O2 Kuvatov, A. D313 LoSar, B. C23O4 Kuznetsov, A. B1SO3 Lubarakii, S.V. B43O1 Kuznetsov, V.A. D1301 van der Lugt, W. C43O2 • Kuznetsov, S.N. D121 Lukin, S.N. B23O2, B83O6, Kveder, V.V. B1517 B2323 Kvlividze, V.I. C2314 Lulek, T. B23OT Kwapulinska, E. C4317 Lumiste, T. D4416 Kyiko, V.S. B2339 Lundin, A.A. 04323 Lundin, A.6. A1313, A122, Laiho, R. C33O2 A2302 Lajunen, L. D44O6 Lupei, A. B23O1 Lalov/icz, Z.T. A14O7, A14O8 Lupei, V. BK01, 18301 Larin, M.F. D421 Lupu, D. A2326 Larionov, A.L. B2323 Lushchik, A.Ch. B1523 Lasarev, G.G. A3 409 LUtgemeier, H. A2339 Lassmann, G. D43O7 Lutovinov, V.S. C13O6 Latos-Grazyfiski, L. D25O1 Luzikov, Yu.N. 04417 Lauger, K. B112 Luznik, J. D4321 1 Lavrukhin, B.D. i 44' '1 Lysenko, E. 04320 | Lazukin, V.N. B2336 Lazukova, N.I. A4307 Macho, V. A412 \ i Lebedev, Ya.S. D43O1, D43O5 Maevsky, V.M. B1611 Leble, A. B16O2, B2311 Magaji, I.A. D14O4

i Leble/'S.B. C24O3 Magnin, P. D1411 Leenstra, W.R. A3 304 Maistrenko, V.I. C1302 Lehto, T. B15O7, B2341 Makova, M.K. C422 Leonardi, C. B1302 Maksimenko, V.M. B14O4 Lerner, I.V. B44O4 Malicheva, N.A. A34O7 Leshina, T.V. 135, A314 Malik, L. A34O5

VII Malkin, B.Z. B1612, C24O1 Mitrofanov, K.P. B4311 Malov, M.M. B1521 Moiseyev, V.A. D3312 Maltsev, S.V. A4313 Mokeeva, V. A4 315 Mal'tsev, V.K. C221 Molder, H. B44O6 Maltseva, L.A. D214 Molin, Yu.N.. 135, A314 - Malyshev, B.' D4317 Moltchanov, Yu. D34O3 Mamayev, V.M. D4418 Monakhov, A.A. C312 Mamykin, A.J. D4314 Monllor, C. C3311 mi -Manapov, R.A. B4314 Moorer W.S. 141 Mandelstam, T.S. D413 Morariu, V.-V. B23O3 Manelis, G.B. A212 Moravsky, A.P. D43O5 Mank, V.V. D3312 Moreno,,M. B2317, B423 Mansurov> Z.A. A34O1 Moroz, N.K. A2319, A2321 Manvelyan, M.O. B2327 Morris, G.A. D412 Margulis, L.A. D4412 Moskalev, A.K. C2312, A4319 ff van der Marel, C. C43O2 Moskvich, Yu.N. A13O9, A1313, Maricq, M. 121 A2315, A2316 Marshall, G.R. D1401 Mueller, L. 115 Martinelli, M. B33O3 Muhtarov, A.Sh. A341C

<•• Martirosyan, R.M. B2327 Miiller-Warmuth, W. B3313, D33O5 Maslennikov, A.I. C114 Muralt, P. C213 Matukhin, V.L. A4318 Muromtsev, V.I. A34O3, B33O4 VS^} Matyash, I. B232O, B312, Murphy, P.O. A1308 A432O Mursin, V.N. D413 •:;•:•? Matyushkin, E.V. C122 Murza, L.I. D13O6, D14O7 Mazitov, R.K. D3316 Mutabzija, R. D411 McDonagh, C. B512 McGarvey, B.R. A2314 Nadolski, S. C222 McNeil, J.A. A2312 Nagayama, K. 115 Mefed, A.E. A113 Naidich, V.I. D14O7 Mehring, M. A121, A1301, Narayana, P.A. B33O7 A1302 Naumenko, V.M. C114, C14O6 Meier, B. 115 Nazarova, I. D23O5 Meier, D. 143 Neilo, G.N. B16O7 Meikiyar, V.P. B3316 Neimark, E.I. A2328 Meise, K. B3313 Nekipelov, V.M. D25O2 Melkov, G.A. C13O8 Neprimerov, N.N. D14O9 Melnikov, A.V. D121 del Nero, G.L. B2331 Mestechkin, M. A33O7 Nesmeyanov, A.N. A43O5 Mialhe, P. B2338 Nesterenko, N.M. C23O5 Michalik, j. C412 «— Nicol, A.T. A214 •1 . Migachev, A.A. B111 Nicula, Al. B2337 1 Mihele, V. D4315 Nikiforov, K.G. . C33O6 Mikhailov, A.I. D24O7, A34O4 Nikitin, P.A. D44O5 Mikhailov, V.I. D33O9 Nikolaev, B.P. D313 Milinchuk, V.K. B33O2 Nistor, S.V. B1512 Minkoff, L. A223 Noack, F. D34O8 Mirzahanyan, A.A. B2312 Norvaishas, A.A. D4311 Mischenko, K.P. D3319 Novak, P. D4415 Mishin, E.N. D14O6 Novikov, V.A. 144 Mishustin, A.I. D3311 Misra, S.K. B233O Odintsov, B.M. B3315 Mitin, A.V. B4313, B4314 O'Donnell, K.P. B15O9, B1510 Mitra, P. A33O4 Okhanov, V.V. D1413

VIII V Okulov, S.M. B323 Petrashen, V.E. B14O2 Okunevich, A.I. C25O2 Petrosyan, V.S. D513 Oldfield, E. D221 Petrosyants, S.P. D25O4 Olivson, A. D1414, D25O9 Petrov, A. D44O7 Olkhov, O.A. C322 Petrov, A.A. D512 Ol'khov, Yu.A. D23O5 Petrov, M.P. C223 Omelchenko, S. B1524 Petrova, I.I. C33O4 Omelyanenko, V.G. D24O7 Petrovsky, P.V. D44O8 Onderwaater, J. C112 Pettersson, L. C33O9 Onishchuk, V.A. A3411 Petutin, A.I. C14O8 ' Orazberdyev, Kh. D4418 Pfeifer, H. A512 van Orraondt, D. B33O9 Phylippov, A.I. B2322 : Osiko, V.V. B1501, B2336 Phylippov, H. D23O3 Osokin, D.Ya. A4316 Pikus, G. A321, A323 Osredkar, R. A114, D222 Pikver, R. B44O6 Ossipyan, Yu.A. B1517 Pilipenko, G.I. B2 33-9 Ostrovsky, D.tJ. D24O4 Pines, A. 132 Ostrovsky, M.A. D24O7 Pirn, L. B1516 Otko, A.I. C23O5 Pisarskaya, T.N. D14O2 Ots, A. B1522, B2341 Pislewski, N. A1312 Ovcharenko, A.I. D34O6 Piven, N.P. B314, B33O8 I Ovchinnikov, I.V. B2321, B2322 P ivovarov, S• D23O3, C43O9, Ozarowski, A. D25O1 D4313 Pleshakov, V.G. D4417 Paalme, T. D1414 Pliss, Yu.A. D43O9 ; Paasivirta, J. D422 Pocsik, I. D14O8, D34O2, , A13O8 D34O5 Paff, A. t Pajak, Z. A2320 Podkovyrin, A.I. D3311 Pak, G. D4317 Podoplelov, A.V. 135 Pakulov, S.N. A33O8 Pogorelov, V.Je. D3314 Pax'mina, N.P. D13O7 Pokhodenko, V.D. D3315 i Panich, A.M. A2319 Polak, M. A122 Pardi, L. B33O3 Polinger, V.Z. B121 r Parfenov, B.B. B413 Polonsky, Ju.A. B1513 Parmon, V. A34O8 Poltavets, V. A33O7 Pashkov, V.S. D114 Polyakov, A. D23O3, D4313 - Pasini, A. B2335 Polyakov, A.M. A13O9 Passoja, A. D44O6 Polyakov, P.I. C212 Past, J. D43O6 Pomortsev, V.V. B3312 Pavlikov, V.V. D24O5 Ponomarenko, A.V. A13O9 Pavlukhin, Ju.T. B43O2 Poot, J. B313 Pehk, T. A1314 Popkov, Yu.P. D43O3 Pembleton, R.G. A13O8 Popov, S.N. C23O7, C311 Pentin, A.Yu. B43O7 Postnikova, G.B. D13O5 Permin, A.B. D513 Poulis, N.J. B313, 145, Perminov, A.P. D43O4 B511 Perrin, B. C43O4 Preobrazhensky, V.L. C13O7 Pershin, A.D. A313 Prins, K.O. C23O1, D33O1 Pescia, J. B2333, C513 Pristupa, A.I. 134, A33O5 Peskovatskii, S.A. B23O5 Privalov, V.I. D2SO7 Pestriakov, B. D25O9 Prokhorov, A.D. B16O7 Pestunovich, V.A. D421 Prokof"ev, A.I. A3 407 Petracovskaia, E.A. B23O6 Proshko, V. A432O Petracovskii, G.A. B23O6 Provotorov, B.N. A211 Prozorov, S.P. A222 Romanov, A. C13O4 Prozorova, L.A. C1301, C13O5 Romanov, E.P. C43O8 Prudnikov, V.V. C34O8 Romanov, N.G. B152O Prussakov, V.E. B43O6 Rosenberg, Yu. A4315 Pshisukha, A.M. B16O9 Rosenberger, H. A221 Pukhov, K. A3 403 Roslyakov, A.I. A431O Pulatova, M.K. D13O7, D1309, Ross, J. A23O8 D24O6 RoQbach, J. A43O6 Pung, L.a. B1523 Rothwell, W. 121 Punkkinen, M. A14O2 Rousseau, J.J. B16O2, B214, PurIns, J. B15O5 B2311 Puskar, J. D43O6 Rudenko, V. B23O2 Pyykke, P. D44O6 Rudin, H. B311 Ruiz, F. B2333, C423 Quitmann, D. A43O6 Rutar, V. C23O4 Rutten, W.L.C. C33O1 Racz, p. D14O8 Ryabchenko, S.M. C25O3 Radushnova, I.L. D441O Ryabikin, J. D4313 Rager, H. A2318 Ryabushkin, O.A. 122 Raisanen, K. D44O6 Ryan, L.M. A13O8 Raitsimring, A.M. B33O1, B3317 Rybaltovsky, A.O B1501 Rakhmatullin, R.M. B16O3 Ryzhmanov, Ju. B2328 Rakos, M. B2319 Rzhavin, A.F. D14O5 Ramos-Bern al, S. B43O8 Rantala, B. C4316 Saburova, R.V. C24O2 Rashba, E.I. B44O1 Saddykov, R.H. D314 Raude, H. A112 Sadykov, I.I. B13O1 Razeghi, M. C23O3 Safarov, V.I. A321 Realo, E. B414 Safin, I.A. A4316, A4318 Realo, K. B15O3, B15O7 Safin, V.A. A13O4 Rebane, T.K. D423 Sagdeev, R.Z. D13O3, 135, Reichert, J.F. B321 A314 Reifman, S. B15O7, B2341 Sakharov, V.I. A321 Reiman, S.I. B4311 Sakun, V. A23O1 Reimann, H. C113, C214, Salikhov, K.M. A311, B33O1 m C33O7 Salivon, G.I. D3314 Reineker, P. A3 306 Saminadayar, K. B44O5 Relnsmith, R. D211 Samitov, Yu.Yu. D314 Reutov, O.A. D513 Santucci, S. B33O3 Reuveni, A. A2314 Sapcin, W.M. B44O2 Revokatov, O.P. D33O2 Sapcina, T.N. B44O2 Rewaj, T. B16O8,, B1610 Sapoval, B. C414 Richards, P.M. A23O6 Sarvazyan, A.P. D212 Rikhireva, G.T. D13O7 , D24O6 Savchenko, M.A. C13O3, C13O6, Riski, K. B43O6 C13O7, C314 V Rist, G.H. A331O Sawada,' Sh. A4319 Roberts, J.D. D513 Schaafsma, T.J. D122, A33O2, Robinet, 6. A2325 D33O3 Robinson, B.H. D13O2 Scherbakov, V.A. D312 Rockenbauer, A. B2335 Scherrer, R. D23O2 Rodak, M.I. A113 Schmalbein, K.D. D414 Rogachev, A.A. A323 Schmidt, F. B43O3 Roinel, Y. 111 Schmidt, W.W. D25O8 Roitsin, A.B. B2326 Schnabel, B. A221 i Schneider, B. 142 ShuXepov, Yu.V. A2313 Schneider, H. A13O5 Shul'ga, A.M. A33O9 Schneider, V.E. C23O9 Shulga, I.Z. A3411 Schulz, J. D321 Shulga, V.M. B1519 i Schutte, M.H.M. C23O1 Shuiran, B.A. A212 von Schiitz, J.U. A3 301 Shutilov, V.A. B13O3 Schwarz, D. D4319 Shuvalov, L.A. C23O6 Schwarzer, E. A23O9 Shuvalov, V.F. D43O5 Schweiger, A. D13O8, B311 Shvartz, K.K. C4313 Schweitzer, D. A413 Sibeldina, L.A. D112, D24O4 Seeman, V. B15O2, B1507, Sidorkin, V.F. D421 B1522 Sierka, E. C4317 Segsa, K.H. B1515 Silin, A. B15O4 Seleznev, V. B23O2 Silkin, N.I. B1518, B23O9 Semin, G.K. A423, A43O8 Simaroj, C. 141 Semin, S.P. C322 Simonyan, S. B411 Sepetov, H.F. D24O4 Simplaceanu, V. A2326 ?••; Serdobov, M.V. A3 409 Sinivee, V. A23O3 Sergeev, A.I. D14O7 Sinyabski, V.I. B413 Sergeev, G.B. D323 Sinyavskey, N. A43O3 Sergeev, N.A. A23O2, A2316 Sjoblom, R. A23O4 Sergeeva, G.G. C1310 Skripov, A.V. C512 Sergeyev, N.M. D4418 Slak, J. C23O4 Seryshev, S.A. A2315 Sleeswyk, A.W. A2327 Shabarchin, E.I. D24O5 Slet, V. D4416 Shabatina, T.I. D323 Smidt, J. 151 Shakhmuratova, L.N. B4315 Smikova, L. C43O9 Shamrai, V.F. A4318 Smirnov, A.I. C13O1 Shanina, B.D. B1611 , B3311 Smirnov, A.M. D4312 Shapet'ko, N.N. D441O Smirnova, T.A. C33O4 Shapiro, A.B. D24O5 Smolensky, G.A. C14O5, C311 I '' Shaposhnikov, I.G. B422 Smolyakov, B.P. C24O1 Sharoyan, E.G. B2312 Sobczyk, L. A43O9 Sharpatyi, V.A. D1310 Sobol, W. A14O7 •IS Shchegolev, I.F. C422 Sobolev, A. B2342 I Shchepkin, V.D. A13O4 Sobolev, V.P. C13O3 Shcherbakov, V.N. D14O6 Soboleva, T.K. C34O5 1 Sheinker, Ju.N. D44O8 Sochava, L.S. B2329 I Shendrik, A. B15O4 Soifer, G. A4315 Sherbakov, V.A. D34O4 Sokolik, I.A. 134, A33O5 Sherbakova, L.L. D34O4 Sokolikova, O.K. D4412 Sherbakova, S.K. A4317 Sokolov, A.I. C14O5 Sherr, K. D211 Sokolov, .V.I. C14O9 fi- Ehestopalov, V.P. D43O3 Solkan, V.N. D4414 fe Shigorin, D.N. B33O4,, D441O Solodovnikov, S.P A3 407 Shimanovsky, N.L. D14O4 Solomko, A.A. C13O2 Shipilov, V. C3406 Solov'ev, E.E. C34O5 Shiroishi, E. A4319 Soovik, T. A3311 Shlyonkin, V.I. B212 SorokO/ L.M. D43O9 Shokanov, A. B431O Spektor, S.A. T5431 6 Shpinel, V.S. B412, B43O7 Staab, H.A. A413 Shtambur, I. B1524 Stahov, 0. C43O9 Shtyrkov, L.G. B43O5 Stalinski, B. C4314 Shubochkina, E. A4321 Stankowski, J. A1312, A513

XI Stark, R.E.. A114 Tomchuk, E. D34O1 •ml Staiko, A. A3 405 Tompa, K. D14O8, D34O2, Stefanovskii, E.P. C34O5 C511 •Sfft'-',;." Stehlik, D. A412 Toriyama, K. B33O7 Stepanov, A.P. C43O8, C512 Toryanik,"A. D33O7 :•;• T&th-Kadar, E. C511 || Stepanov, M.B. D323 Stepanov, V.G. B1518, B23O9, Trappeniers, N.J. C23O1, D33O1 B2323 Tretyak, O.V. C25O4 * '' 'A iff Stepanyants, A.U. D14O2, D1404 Tribel, M.M. 134, A33O5 Stephanovich, A.V. C314 Trifunac, A.D. A312 * % \ StepiSnik, J. A123 Tripo, A. B221 t i Stoeckniann, H.-J. C411 Trofanchuk, L.A. B23O9 Stokes, H.T. C313, A511 Trofimov, A.S. D34O6 '% Stoll, M.E. A121, A1301 Troitsky, V.V. B33O4 Strelenko, Yu.A. A4412, D511 Trontelj, Z. D4321 - "i,

~~fell' •*'->" Strelkova, T.V. D44O1 Tsarevskii, S.L. C43O7~~

Strikha, V.I. C25O4 Tselinsky, Y. D25O9 ' -k i'W StrBbel, B. B112 Tsifrinovich, V.I. C14O7, C221 Stukan, R.A. B43O6 Tsintsadze, G.A. B16O7, B23O2 Ef/ Sudmeier, J.L. D111 Tsukerblat, B.S. B23O4, A4311 Sugakov, V.I. C33O3 Tsvetkov, Yu.D. B33O1, B33O5, * & Sugis, A. B1516 B3317 Suisalu, A. A33O3 Tsyrlov, I. D13O3 Sukhovsky, A.A. A1313, A222 Tuherm, T. A1311 1 Suleymanov, N.M. C431O Tupitsyn, I.F. D4411 Suwelaok, D. A13O2 Turganov, M.M. D13O7 fjr\i Svare, I. A14O4, A14O5 Turov, E.A. 112 ?{; Svechkarev, I.V. C43O1 Syrtsova, L.A. D14O2 Dlyanova, T.N. D44O8 Szymczak, H. B16O4, C222 Omarkhodzhaev, R. D4317 Urbina, C. B211, B33O6

(*• w Talanov, Y.I. C4313 Ursu, I. B1512, B23O1, ii Tamler, H. A2327 B2334, C33O8, :-> Tammet, E. A13O7 C3312 •i Tandura, S.K. D421 Uptynyuk, Yu.A. D4412, D4417, Tarakanov, E.A. C311 D511 IS1 Tarasov, V.P. D2504, D25O7 !*•""' TeeSSr, R. A112, D34O9 Vagapova, F.S. C24O2 'W Tegenfeldt, J. A23O4 Vagizov, F.G. B4314 Teitelbaum, G.B. C34O8 Vainer, V.S. B1513 Telepa, V.T. C211 Vainshteln, D.I, A13O4 •-'•!% Temkin, S.I. D311 Vaisfel'd, M.P. B2346 Teplov, M.A. 124 Vaks, V.G. C23O9 I? Terletski3", O.V. C25O3 Valensin, G. D1410 | Thibaud, C. C421 Valkova,- G.A. B33O4 'A-'. Tlezzi, E. D1410 Vanatalu, K. D1414 | :fc-._ Tikhomirov, V.A. B1501 Vanchikov, V.V. C14O4 --• IV Timerkaev, B.A. C4315 Varlamov, S.D. D4312 Timofeev, V..P. D13O4 Varvas, J. B1525 i Titkov, A.N. A321 Vasneva, G.A. 122, B222 A34O5 Vasson, A. B122 ir: Tkachenko, E.V. B2339 Vasson, A.-M. B122 Tolparov, Yu.N. B2329 Vaughan, R.W. A122, A214 Tolstihin, V. C13O4 Vega, A.J. A213

XII Veinger, A.I. B1513 Windsch, W. C23O8 Velichco, V.V. B23O6 Winkler, K. A2322 Velikanov, G.A. D14O9 Winscom, C.J. A414 Venitski, V.N. C122 de Wit, J.L. D122 Verkhovskii, S.V. C43O8 Wittebort, R.J. D222 Verstelle, J.C. C33O1 WnQtrzak, G. C4317 Vertiy, A.A. D43O3 Wojcik,, M. A43O1 fr.Veshctuinov, Yu.P. B152O Wokaun, A. 115 Vetri, G. B223 Wolf, D. A2327 li Vigni, M. B223 Wolf, H.C. A33O1 Vj- -. Vigouroux, B. C513 Wolfel, W. D34O8 Vikhnin, V.S. A14O6, B14O4, Wolff, E.K. A121, A1301 B1511, A2328, Worthington, B.S. 141 B2329 Wuethrich, K. 115 Vilfan, M. D322 Vilu, R. D1414 Yablokov, Yu.V. B123, B14O2 Vinnalr M. B1516 Yablonski, O.P. A2323 Vinogradova, I.S. A431O Yablonsky, D.A. C13O9 Vinokurov, V.M. A13O4 Yakunin, A. B1524 Vishnevskaja, G. B16O5 Yakunina, N. B1524 I » Vitkovskaya, N.M. D44O5 Yasman, J.B. D24O2 VitoXs, A.Ya. C4313 Yefimov, V.N. B23O9 Vladimirskii, K.V. D4311 Yenikeyeva, G.R. A2313 Vlasenko, L.S. A322 Yla-JaSski, J. B43O6 Vlasova, A.A. C23O9 Ylinen, E.E. A1402 Vlasova, S.A. D24O8 Youdri, L. A2325 Vodopianov, B.P. C4312 Yudanov, V.F. B33O5 Volgina, 6. A4315 Yudin, D. B15O4 Volkel, G. C23O8 Yulmetyev, R.M. D3318 Volkenstein, M.V. D13O4, D13O5 Volkov, V. A3403 Zacharova, N.I. D13O6 Volkov, V. D14O9 Zackharov, V.I. D512 Volodicheva, M.I. D423 Zaev, E.E. D24O2 Volynets, V.V. A2323 Zakharchenia, B.P. 144 Voronkov, M.G. D421, D4405 Zakharov, V.F. D4417 Vorpnpy, M.A. D511 Zalessky, A.V. C1404 Vorontsov, S.A. C43O1 Zamaleev, I.G. C321 Viigmeister, B.E. A2328,, B2318 Zamaraev, K.I. D2502 Zapasskii, V.S. D43O8 Wagnes;, 51. A1401 Zaripov, M.H. B123, B2328, Waldner, F. C113, C214, C4311 C33O7 Zaripov, M.R. A2313 Wang, C.H. A511 Zaritskii, I.M. B1511, B3311 Wanklyn, B.M. B16O4 Zatsepin, B.M. A1403 Wasserman, A.M. D23O1 Zatsepina, N.N. D4411 Waugh, J.s. 121 Zavaritskii, V. C33O2 Weiner, L.M. D13O3 , 135 Zavislyak, I.V. C33O3 Weihreter, E. A43O6 Zazubovich, S. B15O7 Wenokebach, W.Th. .B313, B511 Zbieranowski, W. A43O1, A4312 Whyman, G. A3307 Zeldovich, S.A. C312 Wieker, W. A2324 Zelentsov, V. C34O6 Willcott, M.R. D113 Zewail, A.H. 113 Willeke, F. A43O6 Zhdanov, A.A. D44O1 Windle, J.J. D23O2 Zhetbaev, A. B431O

XIII Zhikharev, V.A. C4312 Zhillnskaya, E.A. B2336 Zhitnikov, R.A. C25O1, C25O2, A322 Zhitnyuk, V.S. C13O8 Zhukov, A.P. C23O6, A43O5 ZhukovJi-, L.N. A3 401 1 i? j3 Zhukovsky, V.H. 82339 Zhuravlev, A.G. A3 309 Ziatdinov, A.M. B123 Zllm, R.W. A1310 I Zlnchenko, V.D; D3312 U Znarairovschi, V. B23O3 Zobov, V.E. A13O9, D4323 Zogal, O.J. C4314 Zolin, V.P. D123 Zonn, Z.N. B2314 Zoroatskaya, E.I. D25O6 Zotoy, H.I. D25O5 Zumer, S. D322 Susman, L.D. C231O Zvolinsky, V.P. D4417 Zvyagin, A.I. B16O9, C14O8 Zyabllkova, T.A. D25O6

~~XIV (I~~

~~1 If~~

AKAflEHHfl HAW 3CT0HCK0H CCP HHCTHTyT KMEEPHETWCM CEOPHMK TE3MC0B XX KOHrPECCA AHHEPA Ha SHrmrilcKoH muxe no«iiHc»Mo • nenaTh 28/07. 1978 r. Eynara 8*1x60/8. TMpa« 1200 axa. yen. nex. JI. 23.52. yM.-HSA. n. 24,16. 3ana3 W 1292-1535- PoTanpMHT 3K "EHT", r. TaiuiHH, yn. rhfKK, 68. KeHa 1.52 W6. If

~~Price rbl. 1.52~~