Ionization Potentials, Appearance Potentials, and Heats of Formation of Gaseous Positive Ions
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; : ? . v ' A111D2 145T53 NAT'iUNST of STANDARDS & TECH R.I.C. All .. „ 102145953 Potentials, appearance Doten PCI 00 US73 V26; 1969 C.2 NBS-PUB-C 1 969 s t tm ? * m ? * / .4 ? * * ? * hi ? v* v> $ >.> > ?* s * nnni %i 1 > in * *? t> t* twumn » m*wawHt$w&nn ?* ^mnmsrmnpiu^w^nm^m m. KS IS ‘ISk Yih ' --;f f ! _1 NBS PUBLICATIONS li lylii {ft '1‘gj fill {$$4} | dul l(]li f) m. -> E."U !.’ I T f; fj •- •> :• • ’ ' „• > : •; «3 v ii : i : ., i \£ .; «! 5 \ ? •, > > V I -.) ! /•: .. *. >»>•. >* ;• \ *i v x : t> t / . s >j v $ -v ? 5? vf.ss «•* fc®33ww»a«k3Snmnu^^naiojaGS *s»* >t « «*«» .»: 33**3'$ 33 S3 33s*waomnumaksnaam!*saa& :••-• :- ?i > v v >s 3>ji * if.’J? i>.-K3L3Jar. » / -.-•>3 i» > » >.• 7 =i"r:V£.ya¥?P **.?(:# >sn.»: s i sr »r'«x.»A »<-.sjc«jrTt •>- .v-s •« V?v y j. as ...m is> - ; :»> r. t >.» t- 7. Y$&rwy»i- « >t >..•*/»» >j.»j »: * 2 ara«.««« Mw«j(si ?•? '.< * » ‘ a ? «> ;' si v: ; s i ni:, M i i v.*53.Vy-i v I7.v» .>**«; s » &.sry.v7&*sei >.»s.»-s.*i*T:arz «?.«rM**4nr »•» *•* s *«S»S c>* :o>!j{ j.ara ; >;•..£• v&S£4* .Vis> i- r>*i as .•*.»>•< ;j>.’ .vv v> vm >.? v3«-^>: j?u*.-**as-jtA-»a si aTji'jjMWijrij.vaiiijwscsjs! 9 ;ss.«ajn«?.V]r sst ;• >.'•• ;• » < > :> .» .< ••? ,> i. * . *r * 1 >; ?i i?» 1 s s 1 %y 3 V.* 5 i W5V9 t >i i r.V&2,-3.**& e i ****38 3**9?* #* rv»* ? i > }'}X3U UNITED STATES DEPARTMENT OF COMMERCE Maurice H. Stans, Secretary 5 , NATIONAL BUREAU OF STANDARDS A. V. Astin, Director \J , % o t Ionization Potentials, Appearance Potentials, and Heats of Formation of Gaseous Positive Ions J. L. Franklin and J. G. Dillard Rice University, Houston, Texas 77001 H. M. Rosenstock, J. T. Herron, and K. Draxl Institute for Materials Research National Bureau of Standards Washington, D.C. 20234 and F. H. Field Esso Research and Engineering Company Linden, New Jersey 07036 NSRDS NSRDS-NBS 26 i Nat. Stand. Ref. Data Ser., Nat. Bur. Stand. (U.S.), 26, 289 pages (June 1969) CODEN: NSRDA Issued June 1969 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402-Price $4 NATIONAL BUREAU OF STANDARDS m *3 XUU443 iQCf^O 73 . U f . \\o.Z-b / 9&? Library of Congress Catalog Card Number: 68-62689 Foreword The National Standard Reference Data System is a Government-wide effort to provide for the technical community of the United States effective access to the quantitative data of physical science, critically evaluated and compiled for convenience, and readily accessible through a variety of distribution channels. The System was established in 1963 by action of the President’s Office of Science and Technology and the Federal Council for Science and Technology. The responsibility to administer the System was assigned to the National Bureau of Standards and an Office of Standard Reference Data was set up at the Bureau for this purpose. Since 1963, this Office has developed systematic plans for meeting high-priority needs for reliable reference data. It has undertaken to coordinate and integrate existing data evaluation and compilation activities (primarily those under sponsorship of Federal agencies) into a comprehensive program, supplementing and expanding technical coverage when necessary, establishing and maintaining standards for the output of the participating groups, and providing mechanisms for the dissemina- tion of the output as required. The System now comprises a complex of data centers and other activities, carried on in Gov- ernment agencies, academic institutions, and nongovernmental laboratories. The independent operational status of existing critical data projects is maintained and encouraged. Data centers that are components of the NSRDS produce compilations of critically evaluated data, critical reviews of the state of quantitative knowledge in specialized areas, and computations of useful functions derived from standard reference data. In addition, the centers and projects establish criteria for evaluation and compilation of data and make recommendations on needed modifications or extensions of experimental techniques. Data publications of the NSRDS take a variety of physical forms, including books, pamphlets, loose-leaf sheets and computer tapes. While most of the compilations have been issued by the Government Printing Office, several have appeared in scientific journals. Under some circum- stances, private publishing houses are regarded as appropriate primary dissemination mechanisms. The technical scope of the NSRDS is indicated by the principal categories of data compila- tion projects now active or being planned: nuclear properties, atomic and molecular properties, solid state properties, thermodynamic and transport properties, chemical kinetics, colloid and surface properties, and mechanical properties. An important aspect of the NSRDS is the advice and planning assistance which the National Research Council of the National Academy of Sciences-National Academy of Engineering provides. These services are organized under an overall Review Committee which considers the program as a whole and makes recommendations on policy, long-term planning, and international collabora- tion. Advisory Panels, each concerned with a single technical area, meet regularly to examine major portions of the program, assign relative priorities, and identify specific key problems in need of further attention. For selected specific topics, the Advisory Panels sponsor subpanels which make detailed studies of users’ needs, the present state of knowledge, and existing data resources as a basis for recommending one or more data compilation activities. This assembly of advisory services contributes greatly to the guidance of NSRDS activities. The NSRDS—NBS series of publications is intended primarily to include evaluated reference data and critical reviews of long-term interest to the scientific and technical community. A. V. Astin, Director. hi Contents Page Foreword iii 1. Introduction 1 1.1. General 1 1.2. Literature coverage 1 1.3. Order of presentation 2 1.4. Reliability of data and criteria for evaluation 2 1.5. Thermochemical considerations 3 1.6. Selection of “best” values 4 1.7. Units 4 1.8. Concluding remarks 4 1.9. References 4 2. Order of ion presentation 5 3. Table 1. Ionization potentials, appearance potentials and heats of formation of gaseous positive ions 14 4. Table 2. Heats of formation of gaseous neutral species derived from the data of table 1 238 5. Bibliography for tables 1 and 2 245 6. Author index for tables 1 and 2 256 7. Appendix 1. Heats of formation used in tables 1 and 2 260 8. Bibliography for appendix 1 282 9. Appendix 2. Table of group equivalent values 285 IV Ionization Potentials, Appearance Potentials, and Heats of Formation of Gaseous Positive Ions J. L. Franklin and J. G. Dillard Rice University, Houston, Texas 77001 H. M. Rosenstock, J. T. Herron, and K. Draxl Institute for Materials Research, National Bureau of Standards, Washington, D.C. 20234 and F. H. Field Esso Research and Engineering Company, Linden, New Jersey 07036 This is a compilation of ionization and appearance potentials of positive ions published from 1955 through June 1966. The compilation lists the ion formed, the parent species from which it was formed, the other products of the process, the threshold energy for the formation of this ion, and the method by which this data was obtained. Where feasible, the heat of formation at 298 K of the positive ion has been computed for each entry using auxiliary thermochemical data. From these computed values “best” values have been chosen. Key Words: Appearance potential; compilation; data; heat of formation; ionization potential; ions; positive ions. 1. Introduction 1.1. General As there is considerable variation in the quality of the data in this field it would have been simpler Since the publication of “Electron Impact to include only the well-determined numbers. Phenomena and the Properties of Gaseous Ions” However, in some cases the only values available by F. H. Field and J. L. Franklin [l], 1 which con- were obtained by imprecise methods, and in the tained a compilation of ionization and appearance belief that an approximate value is better than none potentials reported through 1955, the study of we decided to include all available data in the gaseous ionization phenomena has undergone an compilation. explosive growth in the number and variety of pertinent research studies. This field now includes aspects of vacuum ultraviolet spectroscopy, inelas- 1.2. Literature Coverage tic electron scattering, photoionization, photoelec- tron spectroscopy, mass spectrometry, charge Literature references were obtained initially exchange, and theoretical chemistry. from unpublished annual bibliographies compiled 14 The present volume is intended to cover the by volunteers for ASTM Committee E— on Mass compilations of Kiser bib- literature published since 1955. It is our hope Spectrometry, the [2], liographies published in “Advances in Mass that it will serve several purposes. First, it will given in various present essentially all of the values of appearance Spectrometry” [3], references potentials of positive ions obtained since 1955; review articles, and since 1964, by scanning Physical Sciences” and “Physics second it will provide a set of “best” values of “Current Content, cutoff data was June 1966. heats of formation of gaseous ions; third, it will Abstracts.” The 30, serve as a guide to the literature. We feel that coverage is reasonably thorough for experimental papers but rather spotty for theoretical 1 Figures in brackets indicate the literature references on page 4. and semiempirical treatments. 1 1.3. Order of Presentation Table A. Experimental techniques The heart of this work is table 1, which gives Estimated ionization potentials, appearance potentials, prob- pre- cision in meas- able mechanisms, the method by which the data Abbre- Method Reference urement of— was obtained, and computed heats of formation of viation the various positive ions.