SCIENTIFIC ABBREVIATIONS, ACRONYMS, AND SYMBOLS
This table lists some abbreviations, acronyms, and symbols References encountered in the physical sciences. Most entries in italic type are symbols for physical quantities; for more details on these, see 1. Quantities, Units, and Symbols in Physical Chemistry, Third Edition, the table “Symbols and Terminology for Physical and Chemical IUPAC 2007, RSC Publishing, 2007. Quantities” in this section. Additional information on units may be 2. Kotyk, A., Quantities, Symbols, Units, and Abbreviations in the Life found in the table “International System of Units (SI)” in Section 1. Sciences, Humana Press, Totawa, NJ, 1999. 3. Rhodes, P. H., The Organic Chemist’s Desk Reference, Chapman & Many of the terms to which these abbreviations refer are included Hall, London, 1995. in the tables “Definitions of Scientific Terms” in Section 2 and 4. Minkin, V., Glossary of Terms used in Theoretical Organic Chemistry, “Techniques for Materials Characterization” in Section 12. Useful Pure Appl. Chem. 71, 1919–1981, 1999. references for further information are given below. 5. Brown, R. D., Ed., Acronyms Used in Theoretical Chemistry, Pure Publication practices vary with regard to the use of capital or low- Appl. Chem. 68, 387–456, 1996. er case letters for many abbreviations. An effort has been made to 6. Quantities and Units, ISO Standards Handbook, Third Edition, follow the most common practices in this table, but much variation International Organization for Standardization, Geneva, 1993. is found in the literature. Likewise, policies on the use of periods in 7. Cohen, E. R., and Giacomo, P., Symbols, Units, Nomenclature, and an abbreviation vary considerably. Periods are generally omitted in Fundamental Constants in Physics, Physica 146A, 1–68, 1987. 8. Chemical Acronyms Database, Indiana University,
A ampere; alanine; adenine (in genetic code) Ado adenosine Å ångström ADP adenosine diphosphate; ammonium dihydrogen A absorbance; area; Helmholtz energy; mass number phosphate ads adsorption A Hall coefficient H AE appearance energy A atomic weight (relative atomic mass) r ae eon (109 years) a atto (SI prefix for 10–18) AEP 1-(2-aminoethyl)piperazine a absorption coefficient; acceleration; activity; van der Waals constant AEPD 2-amino-2-ethyl-1,3-propanediol a0 Bohr radius AES atomic emission spectroscopy; Auger electron AAA acetoacetanilide spectroscopy AF audio frequency Aad 2-aminoadipic acid AFM atomic force microscopy AAF 2-(acetylamino)fluorene Ahx 2-aminohexanoic acid AAN aminoacetonitrile AI artificial intelligence AAO acetaldehyde oxime AIBN 2,2’-azobis[isobutyronitrile] AAS atomic absorption spectroscopy AICA 5-amino-1H-imidazole-4-carboxamide ABA abscisic acid; acrylonitrile-butadiene acrylate AIM atoms in molecules (method) Abe abequose AIP aluminum isopropoxide ABL B-acetylbutyrolactone Al Alfén number ABS acrylonitrile-butadiene-styrene copolymer Ala alanine abs absolute alc alcohol Abu 2-aminobutanoic acid ALE atomic layer epitaxy Ac acetyl; acetate aliph. aliphatic ac, AC alternating current alk. alkaline ACAC acetylacetone All allose Aces 2-[(2-amino-2-oxoethyl)amino]ethanesulfonic acid Alt altrose ACS acrylonitrile-chlorinated polyethylene-styrene copolymer AM amplitude modulation ACT activated complex theory Am amyl ACTH adrenocorticotropic hormone am amorphous solid A/D analog to digital AMA acrylate maleic anhydride terpolymer Ad adamantyl AMMA acrylate-methyl methacrylate copolymer Ada [(carbamoylmethyl)imino]diacetic acid AMP adenosine monophosphate Ade adenine AMPD 2-amino-2-methyl-1,3-propanediol ADI acceptable daily intake AMS accelerator mass spectrometry
2-29 2-30 Scientific Abbreviations, Acronyms, and Symbols
AMTCS amyltrichlorosilane [trichloropentylsilane] BBP benzyl butyl phthalate amu atomic mass unit (recommended symbol is u) BCB bromocresol blue AN acetonitrile; acrylonitrile bcc body centered cubic anh, anhyd anhydrous BCF bioconcentration factor ANOVA analysis of variance BCG bromocresol green antilog antilogarithm BCME bis(chloromethyl) ether ANTU 1-naphthalenylthiourea BCNU N,N’-bis(2-chloroethyl)-N-nitrosourea AO atomic orbital BCP bromocresol purple AOM angular overlap model BCPB bromochlorophenol blue AP ethylene-propylene copolymer BCPE 1,1-bis(4-chlorophenyl)ethanol APAD 3-acetylpyridine adenine dinucleotide BCS Bardeen-Cooper-Schrieffer (theory) APAP acetyl p-amino phenol (acetaminophen) BDE bond dissociation energy Ape 2-aminopentanoic acid BDEA butyldiethanolamime API atmospheric pressure ionization BDMA benzyldimethylamine Api apiose Bé Baumé APM atomic probe microanalysis BEBO bond energy bond order (method) Apm 2-aminopimelic acid BEI biological exposure index APO amorphous polyolefin BEM biological effect monitoring APPI atmospheric pressure photoionization BEP 2-butyl-2-ethyl-1,3-propanediol APS appearance potential spectroscopy; adenosine Bes 2-[bis(2-hydroxyethyl)amino]ethanesulfonic acid phosphosulfate BET Brunauer-Emmett-Teller (isotherm) APW augmented plane wave BeV billion electronvolt aq aqueous BGE butyl glycidyl ether Ar aryl BHA tert-butyl-4-hydroxyanisole Ara arabinose BHC benzene hexachloride [hexachlorobenzene] Ara-ol arabinitol Bhn Brinell hardness number Arg arginine BHT butylated hydroxytoluene [2,6-di-tert-butyl-4- ARPES angular resolved photoelectron spectroscopy methylphenol] AS acrylonitrile styrene copolymer Bi biot ASA acetylsalicylic acid; acrylonitrile-styrene-acrylonitrile Bicine N,N-bis(2-hydroxyethyl)glycine block copolymer BIRD blackbody infrared radiative dissociation ASC 4-(acetylamino)benzenesulfonyl chloride Bistris 2-[bis(2-hydroxyethyl)amino]-2-(hydroxymethyl) ASCII American National Standard Code for Information propane-1,3-diol Interchange Bistris- 1,3-bis[tris(hydroxymethyl)methylamino]propane ASE aromatic stabilization model propane Asn asparagine BLO H-butyrolactone Asp aspartic acid BN bond number; benzonitrile at atomization BNS nuclear backscattering spectroscopy ATCP 4-amino-3,5,6-trichloro-2-pyridinecarboxlic acid BO Born-Oppenheimer (approximation); bond order ATEE N-acetyl-L-tyrosine ethyl ester BOD biochemical oxygen demand ATLC adsorption thin layer chromatography BON C-hydroxynaphthoic acid atm standard atmosphere BP base peak (in mass spectrometry); benzo[a]pyrene ATP adenosine triphosphate bp boiling point; base pair ATR attenuated total internal reflection BPB bromophenol blue at.wt. atomic weight BPG 2,3-bis(phospho)-D-glycerate AU astronomical unit (ua is also used); polyurethane BPL C-propiolactone AUC area under the time-concentration curve BPO benzoyl peroxide av average bpy 2,2’-bipyridine avdp avoirdupois Bq becquerel B bel; asparagine or aspartic acid (unspecified) Br butyryl B magnetic flux density; second virial coefficient; BRE bond resonance energy susceptance BrUrd 5-bromouridine b barn BS Birge-Sponer extrapolation b van der Waals constant; molality BSE back scattered electron(s) BA benzyladenine BSSE basis set superposition error BAL British anti-Lewisite [2,3-dimercapto-1-propanol] BTMSA 1,2-bis(trimethylsilyl)acetylene BAP, BaP benzo[a]pyrene Btu British thermal unit bar bar (pressure unit) BTX benzene, toluene, and xylene bbl barrel Scientific Abbreviations, Acronyms, and Symbols 2-31
Bu butyl CIDNP chemically induced dynamic nuclear polarization bu bushel CIE countercurrent immunoelectrophoresis BVE butyl vinyl ether cir circular Bz benzoyl CKFF Cotton-Kraihanzel force field Bzl benzyl CL cathode luminescence (spectroscopy) C coulomb; cysteine; cytosine (in genetic code) CLT central limit theorem °C degree Celsius cm centimeter C capacitance; heat capacity; number concentration c.m. center of mass c centi (SI prefix for 10–2); combustion reaction CMC carboxymethylcellulose c amount concentration; specific heat; velocity c.m.c. critical micelle concentration c0 speed of light in vacuum CMO canonical molecular orbital CA collisional activation; cellulose acetate CMP cytidine 5’-monophosphate; chemical measurement ca. approximately process CN coordination number; cellulose nitrate CAB cellulose acetate butyrate CNDO complete neglect of differential overlap CADD computer-assisted drug design Co Cowling number cal calorie COC cycloolefin copolymer calc calculated COD chemical oxygen demand; 1,4-cyclooctadiene cAMP adenosine cyclic 3’,5’-(hydrogen phosphate) conc concentrated; concentration CAN ceric ammonium nitrate const constant CAR carbon fiber COOP crystal orbital overlap population CARS coherent anti-Stokes Raman spectroscopy cos cosine CAS complete active space cosh hyperbolic cosine CASRN Chemical Abstracts Service Registry Number COSY correlation spectroscopy CAT computerized axial tomography; clear air turbulence COT 1,3,5,7-cyclooctatetraene CBE chemical beam epitaxy cot cotangent CBS complete basis set (of orbitals) coth hyperbolic cotangent CC coupled cluster; combustion calorimetry CP chemically pure cc cubic centimeter Cp cyclopentadienyl CCD charge-coupled device Cp* pentamethylcyclopentadienyl CD circular dichroism cP centipoise cd candela; condensed (phase) cp candle power CDAA 2-chloro-N,N-diallylacetamide CPA coherent potential approximation CDNO complete neglect of differential overlap CPC centrifugal partition chromatography CDP cytidine 5’-diphosphate cpd contact potential difference CDT 1,5,9-cyclododecatriene CPE chlorinated polyethylene CDTA (1,2-cyclohexylenedinitrilo)tetraacetic acid monohydrate CPL circular polarization of luminescence CDW charge density waves CPR chlorophenol red CED cohesive energy density cps cycles per second CEM channel electron multiplier CPT charge conjugation/space inversion/time inversion CEP counter electrophoresis (theorem) CEPA coupled electron-pair approximation CPU central processing unit cf. compare CPVC chlorinated poly(vinyl chloride) CFC chlorofluorocarbon compound CR chloroprene rubber (neoprene) cfm cubic feet per minute cr, cryst crystalline (phase) CFRP carbon reinforced plastics CRF charge remote fragmentation cgs centimeter-gram-second system CRU constitutional repeating unit (in polymer nomenclature) Chaps 3-[3-(cholamidopropyl)dimethylammonio]-1- CSA camphorsulfonic acid propanesulfonic acid csc cosecant Ches 2-(N-cyclohexylamino)ethanesulfonic acid CSR charge stripping reaction CHF coupled Hartree-Fock (method) CT charge transfer Chl chlorophyll ct carat Cho choline CTA cellulose triacetate CHT 1,3,5-cycloheptatriene CTEM conventional transmission electron microscopy Ci curie CTFE chlorotrifluoroethylene CI configuration interaction; chemical ionization; color index CTP cytidine 5’-triphosphate CID charge-injection device; collision-induced dissociation CTR controlled thermonuclear reaction CIDEP chemically induced dynamic electron polarization cu cubic 2-32 Scientific Abbreviations, Acronyms, and Symbols
CV cyclic voltammetry DESI desorption electrospray ionization (in mass spectrometry) CVD chemical vapor deposition det determinant cw continuous wave dev deviation cwt hundredweight (112 pounds) DFT density functional theory Cy cyclohexyl dGlc 2-deoxyglucose Cya cysteic acid DHBA 2,3-dihydroxybenzoic acid Cyd cytidine DHH dehydroheliotridine cyl cylinder DHR dehydroretronecine Cys cysteine DHU dihydrouridine Cyt cytosine DI desorption ionization D debye unit; aspartic acid diam diameter D diffusion coefficient; dissociation energy; electric DIBA diisobutyl adipate displacement DIBK diisobutyl ketone d day; deuteron; deci (SI prefix for 10–1) dil dilute; dilution d distance; density; dextrorotatory DIM diatomics in molecules (method); digital imaging 2,4-D 2,4-dichlorophenoxyacetic acid microscopy D/A digital to analog DIPA diisopropanolamine Da dalton dm decimeter DA donor-acceptor (complex) DMA N,N-dimethylaniline da deka (SI prefix for 101) DMAB 4-(dimethylamino)azobenzene DAA diacetone alcohol DMAC N,N-dimethylacetamide DAB 4-(dimethylamino)azobenzene DMAE N,N-dimethylethanolamine Dab 2,4-diaminobutanoic acid DMBA 7,12-dimethylbenz[a]anthracene DACH trans-1,2-diaminocyclohexane DME 1,2-dimethoxyethane DAIP diallyl isophthalate plasticizer DMF N,N-dimethylformamide DAP diammonium phosphate DMP dimethyl phthalate DART direct analysis in real time mass spectrometry DMS dimethyl sulfide dB decibel DMSO dimethyl sulfoxide DBA dibenz[a,h]anthracene; dibenzylamine DMT dimethyl terephthalate; dimethyl tartrate DBCP 1,2-dibromo-3-chloropropane DN donor number DBED dibenzyl ethylene diamine DNA deoxyribonucleic acid DBM dibutyl maleate DNase deoxyribonuclease DBMC 2,4-di-tert-butyl-5-methylphenol DNB 1,3-dinitrobenzene DBMS database management system DNMR dynamic NMR spectroscopy DBP dibutyl phthalate; 2,3-dibromo-1-propanol DNP dinitropyrene DBPC 2,6-di-tert-butyl-p-cresol Dod dodecyl dc, DC direct current DOP dioctyl phthalate DCB dicyanobenzene DOS density of states; digital operating system; dioctyl sebacate DCBP 4,4’-dichlorobenzophenone doz dozen DCEE dichloroethyl ether DP, d.p. degree of polymerization DCHA dicyclohexylamine DPA diphenylamine DCM dichloromethane DPG N,N’-diphenylguanidine DCNP 2,6-dichloro-4-nitrophenol dpl displacement DCP 2,4-dichlorophenol Dpm 2,6-diaminopimelic acid DCPD dicyclopentadiene dpm disintegrations per minute DDM 4,4’-diaminodiphenylmethane dps disintegrations per second DDT dichlorodiphenyltrichloroethane DPU N,N’-diphenylurea DE delocalization energy; delayed extraction dr dram DEA N,N-diethylaniline; diethanolamine DRE Dewar resonance energy Dec decyl dRib 2-deoxyribose dec decomposes DRIFT diffuse reflectance infrared Fourier transform DEET diethyltoluamide [N,N-diethyl-3-methylbenzamide] DRP dynamic reaction path deg degree DRS diffuse reflectance spectroscopy DEK diethyl ketone DS degree of substitution den density DSC differential scanning calorimetry DEP 2,2-diethyl-1,3-propanediol DTA differential thermal analysis DES diethyl sulfate DTBP di-tert-butyl peroxide Scientific Abbreviations, Acronyms, and Symbols 2-33
DVB divinylbenzene EPXMA electron probe x-ray microanalysis dyn dyne eq, eqn equation DZ double-zeta (type of basis set) eqQ quadrupole coupling constant E exa (SI prefix for 1018); glutamic acid erf error function E electric field strength; electromotive force; energy; Young’s erg erg (energy unit) modulus of elasticity; entgegen (trans configuration) ES equilibrium in solution E Hartree energy h ESA electrostatic energy analyzer e electron; base of natural logarithms ESCA electron spectroscopy for chemical analysis e elementary charge; linear strain ESD electron stimulated desorption EA electron affinity e.s.d. estimated standard deviation EAA ethylene acrylic acid copolymer; ethyl acetoacetate ESI electrospray ionization EAK ethyl amyl ketone (3-octanone) ESR electron spin resonance EAN effective atomic number est estimated EC ethyl cellulose esu electrostatic unit system ECD electron capture dissociation ET ephemeris time; electron transfer ECP effective core potential Et ethyl ECR electron cyclotron resonance ETA electrothermal analysis ECTFE ethylene-chlorotrifluoroethylene copolymer ETFE ethylene tetrafluoroethylene polymer ED electron diffraction Etn ethanolamine EDAX energy dispersive analysis by x-rays ETO ethylene oxide EDB ethylene dibromide [1,2-dibromoethane] ETS electron tunneling spectroscopy EDC ethylene dichloride [1,2-dichloroethane] ETU ethylene thiourea EDI estimated daily intake EU polyether polyurethane EDS energy-dispersive x-ray spectroscopy Eu Euler number EDTA ethylenediaminetetraacetic acid e.u. entropy unit EEA ethylene-ethyl acetate copolymer eV electronvolt EEDQ ethyl 2-ethoxy-1(2H)-quinolinecarboxylate EVA ethylene-vinyl acetate copolymer EEL environmental exposure level EVE ethyl vinyl ether EELS electron energy loss spectroscopy EXAFS extended x-ray absorption fine structure (spectroscopy) EES excitation emission spectrum EXELFS extended energy loss fine structure EFF empirical force field exp exponential function EFFF energy factored force field expt experimental EG equilibrium in the gas phase ext external EGA evolved gas analysis F farad; phenylalanine EGG Einstein-Guth-Gold equation °F degree Fahrenheit EHMO, extended Hückel molecular orbital (theory) EHT F Faraday constant; force; angular momentum EIMS electron impact mass spectrometry f formation reaction; femto (SI prefix for 10–15) EIS electron impact spectroscopy; electrochemical f activity coefficient; aperture ratio; focal length; force impedance spectroscopy constant; frequency; fugacity ELISA enzyme-linked immunosorbent assay FAB fast atom bombardment ELS energy loss spectroscopy FAD flavine adenine dinucleotide EM extended molarity; electron microscopy FAIMS high-field asymmetric waveform ion mobility EMAC ethylene-methyl acrylate copolymer spectrometry FA-SIFT flowing afterglow – selected ion-flow tube emf electromotive force fcc face centered cubic EMPA, electron probe microanalysis EMA FD field desorption emu electromagnetic unit system FEL free electron laser en ethylenediamine FEM field emission microscopy ENDOR electron-nuclear double resonance FEMO free electron molecular orbital EOS equation of state FEP fluorinated ethylene propylene EP epoxy resin FET field effect transistor EPDS electron photodetachment spectroscopy FI field ionization EPM ethylene-propylene copolymer fid free induction decay EPR electron paramagnetic resonance; ethylene propylene FIM field ion microscopy rubber FIR far infrared EPS expanded polystyrene fl fluid (phase) EPT-76 provisional low temperature scale of 1976 FM frequency modulation EPTC dipropylcarbamothioic acid, S-ethyl ester Fo Fourier number 2-34 Scientific Abbreviations, Acronyms, and Symbols fp freezing point Gra glyceraldehyde fpm feet per minute Gri glyceric acid fps feet per second; foot-pound-second system Grn glycerone [dihydroxyacetone] Fr franklin Gro glycerol Fr Froude number GTO gaussian-type orbital FRP fibrous glass reinforced polyester; fiber reinforced plastic GTP guanosine 5’-triphosphate Fru fructose Gua guanine FSGO floating spherical gaussian orbitals Gul gulose FT Fourier transform Guo guanosine ft foot GUT grand unified theory ft-lb foot pound GVB generalized valence bond (method) FTIR Fourier transform infrared spectroscopy GWS Glashow-Weinberg-Salam (theory) FTMS Fourier transform mass spectrometry Gy gray; gigayear FTNMR Fourier transform nuclear magnetic resonance H henry; histidine fus fusion (melting) H enthalpy; Hamiltonian function; magnetic field
FVP flash vacuum pyrolysis H0 Hubble constant FWHM full width at half maximum h helion; hour; hecto (SI prefix for 102) G gauss; guanine (in genetic code); giga (SI prefix for 109); h Planck constant glycine Ha Hartmann number G electrical conductance; Gibbs energy; gravitational constant; sheer modulus ha hectare g gram; gas (phase) HAM hydrogenic atoms in molecules g acceleration due to gravity; degeneracy; Landé g-factor; hav haversine statistical weight Hb hemoglobin GABA H-aminobutyric acid HCA heterocyclic amine; hexachloroacetone Gal gal; galactose HCB hexachlorobenzene gal gallon hcp hexagonal closed packed GalN galactosamine Hcy homocysteine GB gas-phase basicity HCZ, hydrochlorothiazide GC gas chromatography HCTZ GC-MS gas chromatography-mass spectroscopy HDL high-density lipoprotein GDMS glow discharge mass spectroscopy HDPE high-density polyethylene GDP guanosine 5’-diphosphate HDS hydrodesulfurization gem geminal (on the same carbon atom) HEIS high-energy ion scattering GeV gigaelectronvolt HEP high energy physics GF glass reinforced Hepes 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid GIAO gauge invariant atomic orbital Hepps 4-(2-hydroxyethyl)-1-piperazinepropanesulfonic acid GIBMS guided ion beam mass spectrometry HF high frequency; Hartree-Fock (method) gl glacial HFA hexafluoroacetone Gla 4-carboxyglutamic acid HFO Hartree-Fock orbital GLC gas-liquid chromatography hfs hyperfine structure Glc glucose HHPA hexahydrophthalic anhydride GlcA gluconic acid HIPS high-impact polystyrene GlcN glucosamine His histidine GlcNAc N-acetylglucosamine HMC high strength molding compound GlcU glucuronic acid HMDA hexamethylenediamine Gln glutamine HMO Hückel molecular orbital GLP good laboratory practice HMT hexamethylenetetramine Glu glutamic acid HMX cyclotetramethylenetetranitramine Glx glutamine or glutamic acid (unspecified) HN1 2-chloro-N-(2-chloroethyl)-N-ethylethanamine Gly glycine HOAc acetic acid GMP guanosine 5’-monophosphate HOC halogenated organic compound(s) GMT Greenwich mean time HOMAS harmonic oscillator model of aromatic stabilization GPC gel-permeation chromatography HOMO highest occupied molecular orbital gpm gallons per minute HOSE harmonic oscillator stabilization energy gps gallon per second Hp heptyl Gr Grashof number hp horsepower gr grain HPLC high-performance liquid chromatography Scientific Abbreviations, Acronyms, and Symbols 2-35
HPMS high pressure mass spectrometry IPTS International Practical Temperature Scale HQ p-hydroquinone IQ 2-amino-3-methyl-3H-imidazo(4,5-f)quinoline hr hour IR infrared HRE Hückel resonance energy IRAS infrared reflection-absorption spectroscopy HREELS high resolution electron energy loss spectroscopy IRC intrinsic reaction coordinate HREM high resolution electron microscopy IRMPD infrared multiphoton dissociation HSAB hard-soft acid-base (theory) IRMS isotope ratio mass spectrometry HSE homodesmotic stabilization energy IRS infrared spectroscopy Hse homoserine isc intersystem crossing HVA homovanillic acid ISE ion-selective electrode; isodesmic stabilization energy Hx hexyl ISS ion scattering spectroscopy Hyl 5-hydroxylysine IT ion trap; information technology Hyp hypoxanthine; 4-hydroxyproline ITP inosine 5’-triphosphate Hz hertz ITS International Temperature Scale (1990) I isoleucine; inositol; ionomer IU international unit I electric current; ionic strength; moment of inertia; IVE isobutyl vinyl ether nuclear spin angular momentum; radiant intensity J joule; leucine or isoleucine (unspecified) i square root of minus one J angular momentum; electric current density; flux; i electric current Massieu function I/O input/output j angular momentum; electric current density IAT international atomic time JT Jahn-Teller (effect) IC integrated circuit K kelvin; lysine ICD induced circular dichroism K absorption coefficient; bulk modulus; equilibrium ICP inductive-coupled plasma constant; kinetic energy k kilo (SI prefix for 103) ICR ion cyclotron resonance k absorption index; Boltzmann constant; rate constant; ICVTST improved canonical variational transition-state theory thermal conductivity; wave vector ID inside diameter kat katal (unit of catalytic activity) id ideal (solution) kb kilobar; kilobases (DNA or RNA) Ido iodose KC-MS Knudson cell mass spectrometry IdoA iduronic acid kcal kilocalorie IDP inosine 5’-diphosphate KDP potassium dihydrogen phosphate IE ionization energy KE kinetic energy i.e.p. isoelectric point KERD kinetic energy release distributions IEPA independent electron pair approximation keV kiloelectronvolt IF intermediate frequency KG kinetics in the gas phase IGLO individual gauge for localized orbitals kg kilogram IIR isobutylene-isoprene rubber (butyl rubber) kgf kilogram force IKES ion kinetic energy spectrometry KIE kinetic isotope effect Ile isoleucine kJ kilojoule Im imaginary part km kilometer IMFP inelastic mean free path (of electrons) Kn Knudsen number imm immersion kPa kilopascal IMP inosine 5’-monophosphate KS kinetics in solution IMPATT impact ionization avalanche transit time kt karat IMS ion mobility spectrometry KTP potassium titanium phosphate in. inch kV kilovolt InChI IUPAC International Chemical Identifier kva kilovolt ampere INDO immediate neglect of differential overlap kW kilowatt Ino inosine kwh kilowatt hour INS inelastic neutron scattering; ion neutralization spectroscopy L liter; lambert; leucine Ins myo-inositol L Avogadro constant; inductance; Lagrange function; int internal angular momentum l liter; liquid (phase) IP ionization potential l angular momentum; length; mean free path; levorotatory IPA isopropyl alcohol Lac lactose IPMA ion probe microanalysis LAH lithium aluminum hydride IPN interpenetrating polymer network lat. latitude IPR isotope perturbation of resonance lb pound 2-36 Scientific Abbreviations, Acronyms, and Symbols lbf pound force m magnetic dipole moment; mass; molality; angular LC liquid chromatography; liquid crystal momentum component; meta (locant on aromatic ring) Ma Mach number LC-MS liquid chromatography-mass spectrometry MA maleic anhydride lc liquid crystal (phase) MAAc methyl amyl acetate LCAO linear combination of atomic orbitals Mal maltose LD lethal dose; laser desorption Man mannose LDA local density approximation; lithium diisopropylamide MASNMR magic angle spinning nuclear magnetic resonance LDL low-density lipoprotein max maximum LDPE low-density polyethylene Mb myoglobin LDV laser-Doppler velocimetry MBE molecular beam epitaxy Le Lewis function MBER molecular beam electron resonance LE localization energy MBK methyl butyl ketone LEC liquid exchange chromatography MBOCA 4,4’-methylenebis[2-chloroaniline] LED light emitting diode MBPT many body perturbation theory LEED low-energy electron diffraction MBS methyl methacrylate butadiene styrene terpolymer LEIS low-energy ion scattering MC Monte Carlo (method) Leu leucine MCAA monochloroacetic acid LFER linear free energy relationships MCD magnetic circular dichroism LFL lower flammable limit MCP microchannel plate LI laser ionization MCPA (4-chloro-2-methylphenoxy)acetic acid lim limit MCPF modified coupled pair functional LIMS laser ionization mass spectroscopy; laboratory information management system MCS Monte Carlo simulation liq liquid MCSCF multiconfigurational self-consistent field (approximation) LIT linear ion trap MD molecular dynamics (method) LLCT ligand to ligand charge transfer MDI methylene diphenylisocyanate lm lumen MDPE medium density polyethylene LMCT ligand to metal charge transfer Me methyl LMMS laser microprobe mass spectrometry MeCCNU 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea LMO localized molecular orbital MeIQ 2-amino-3,4-dimethylimidazo[4,5-f]quinoline LMR laser magnetic resonance MeIQx 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline ln logarithm (natural) MEK methyl ethyl ketone LNDO local neglect of differential overlap MEP molecular electrostatic potential log logarithm (common) MERP minimum energy reaction path LOMO lowest occupied molecular orbital Mes 4-morpholineethanesulfonic acid long. longitude MESFET metal-semiconductor field-effect transistor LPE linear polyethylene Met methionine LPG liquid petroleum gas MeV megaelectronvolt LPHP laser-powered homogeneous pyrolysis meV millielectronvolt LPU law of propagation of uncertainty MF molecular formula; melamine-formaldehyde resin LSFE linear field stabilization energy mg milligram LSI liquid secondary ionization MHD magnetohydrodynamics LST local sidereal time mi mile LT local time MIAK methyl isoamyl ketone LTE local thermodynamic equilibrium MIBK methyl isobutyl ketone LUMO lowest unoccupied molecular orbital MIC methyl isocyanate lx lux MIK methyl isobutyl ketone ly langley MIKES mass-analyzed ion kinetic energy spectrometry l.y. light year min minimum; minute Lys lysine MINDO modified INDO (method) Lyx lyxose MIPK methyl isopropyl ketone M molar (as in 0.1 M solution); mega (SI prefix for 106); MIR mid infrared methionine misc miscible M magnetization; molar mass; mutual inductance; torque; angular momentum component; median MKS meter-kilogram-second system
Mr molecular weight (relative molar mass) MKSA meter-kilogram-second-ampere system m meter; molal (as in 0.1 m solution); metastable (isotope); mL, ml milliliter –3 milli (SI prefix for 10 ) MM molecular mechanics Scientific Abbreviations, Acronyms, and Symbols 2-37 mm millimeter nbp normal boiling point MMDR microwave-microwave double resonance NBR nitrile butadiene rubber [poly(butadiene-co- mmf magnetomotive force acrylonitrile)] NDELA N-nitrosodiethanolamine mmHg millimeter of mercury NEDOR nuclear electron double resonance MNA m-nitroaniline NEM N-ethylmorpholine MNDO modified neglect of diatomic overlap Neu neuraminic acid MNT m-nitrotoluene NEXAFS near-edge x-ray absorption fine structure MNU N-methyl-N-nitrosourea ng nanogram MO molecular orbital; methyl orange NHO natural hybrid orbital MODR microwave-optical double resonance NHOMO next-to-highest occupied molecular orbital mol mole NICI negative ion chemical ionization mol.wt. molecular weight NICS nuclear independent chemical shift mon monomeric form NIR near infrared; ribosylnicotinamide Mops 4-morpholinepropanesulfonic acid nm nanometer MOS metal-oxide semiconductor NMN C-nicotinamide mononucleotide MOSFET metal-oxide semiconductor field-effect transistor NMR nuclear magnetic resonance mp melting point Nn nonyl MPa megapascal NNDO neglect of nonbonded differential overlap MPA Mulliken population analysis NO natural orbital Mpc megaparsec NOE nuclear Overhauser effect MPD 2-methyl-2,4-pentanediol NOEL no-observed-effect level MPI multiphoton ionization NOx nitrogen oxides MPTP 1,2,3,6-tetrahydro-1-methyl-4-phenylpyridine NP nitropyrene MR methyl red NPA natural population analysis MRD multireference double substitution (method) NQR nuclear quadrupole resonance MRI magnetic resonance imaging NR natural rubber mRNA messenger RNA NRA nuclear reaction analysis MS mass spectroscopy ns nanosecond ms millisecond NSE neutron spin echo MSA methanesulfonic acid NTA nitrilotriacetic acid MSDS Material Safety Data Sheet NTP normal temperature and pressure MSF methanesulfonyl fluoride Nu nucleophile MS-K mass spectroscopy – kinetic method Nu Nusselt number MSL mean sea level o ortho (locant on aromatic ring) MTBE methyl tert-butyl ether OAA oxaloacetic acid MTD maximum tolerable dose obs, obsd observed Mur muramic acid Oc octyl mV millivolt OD optical density; outside diameter MVK methyl vinyl ketone ODMR optically detected magnetic resonance MW megawatt; microwave; molecular weight Oe oersted mW milliwatt OFGF outer valence Green’s function (method) MWD molecular weight distribution ONA o-nitroaniline Mx maxwell ORD optical rotatory dispersion N newton; asparagine Oro orotate; orotidine N angular momentum; neutron number; number density oz ounce N Avogadro constant A P poise; peta (SI prefix for 1015); proline n neutron; nano (SI prefix for 10–9) P power; pressure; probability; sound energy flux n amount of substance; number density; principal quantum –12 number; refractive index; normal (in chemical formulas) p proton; pico (SI prefix for 10 ) NAA nuclear activation analysis; 1-naphthaleneacetic acid p dielectric polarization; electric dipole moment; NAAD nicotinic acid adenine dinucleotide momentum; pressure; bond order; para (as aromatic ring locant) NAD nicotinamide adenine dinucleotide Pa pascal NADH reduced NAD PA proton affinity; pyrrolizidine alkaloid; polyamide (nylon) NADP NAD phosphate PAA poly(acrylic acid) NANA N-acetylneuraminic acid PABA p-aminobenzoic acid NAO natural atomic orbital PABS p-aminobenzenesulfonamide NBO natural bond orbital PAC photoacoustic calorimetry 2-38 Scientific Abbreviations, Acronyms, and Symbols
PAH polycyclic aromatic hydrocarbon(s) PI polyimide PAI polyamide-imide pI isoelectric point PAL polyaniline PIB polyisobutylene PAM polyacrylamide PIMS photoionization mass spectrometry PAN 1-(2-pyridylazo)-2-naphthol; polyacrylonitrile PIN p-intrinsic-n (diode) PAR 4-(2’-pyridylazo)resorcinol Pipes 1,4-piperazinediethanesulfonic acid PARA polyaryl amide PIV particle-image velocimetry PAS photoacoustic spectroscopy; polyarylsulfone PIXE particle induced x-ray emission PB polybutylene pK negative log of ionization constant PBA poly(butyl acrylate) PLM principle of least motion PBAN polybutylene-acrylonitrile copolymer PLOT porous-layer open-tabular (column) PBB polybrominated biphenyl PLS partial least squares PBD poly(1,3-butadiene) pm picometer PBI polybenzimidazole PMA poly(methyl acrylate) PBMA poly(butyl methacrylate) PMAC phenylmercuric acetate PBS polybutadiene-styrene copolymer PMMA poly(methyl methacrylate) PBT poly(butylene terephthalate) PMO perturbation MO (theory) PC paper chromatography; photocalorimetry; polycarbonate PMP polymethylpentene pc parsec PMS polymethylstyrene; p-methylstyrene PCB polychlorinated biphenyl PNA p-nitroaniline PCHO paraldehyde (2,4,6-trimethyl-1,3,5-trioxane) PNDO partial neglect of differential overlap PCL polycaprolactone PNO pair natural orbitals PCM polarizable continuum model PNRA prompt nuclear reaction analysis PCNB pentachloronitrobenzene PNT p-nitrotoluene PCP pentachlorophenol PO polyolefin PCR polymerase chain reaction POAV Q-orbital axis vector PCT poly(cyclohexylene terephthalate) pol polymeric form PCTFE polymonochlorotrifluoroethylene POM polyoxymethylene PD potential difference POx phosphorus oxides PDB p-dichlorobenzene PP polypropylene pdl poundal ppb parts per billion PDMS poly(dimethylsiloxane) PPC chlorinated polypropylene PE polyethylene PPE poly(phenylene ether) Pe pentyl ppm parts per million Pe Péclet number PPO poly(phenylene oxide) pe probable error PPOX polypropylene oxide PEA poly(ethyl acrylate) PPP Pariser-Parr-Pople (method) PEEK poly(ether ether ketone) PPS poly(phenylene sulfide) PEG poly(ethylene glycol) PPSU poly(phenylene sulfone) PEI polyetherimide PPT poly(propylene terephthalate) PEK polyetherketone ppt parts per thousand; precipitate PEL permissible exposure limit Pr propyl PEO poly(ethylene oxide) Pr Prandtl number PES photoelectron spectroscopy; potential energy surface; PRDDO partial retention of diatomic differential overlap polyethersulfone Pro proline PET positron emission tomography; poly(ethylene terephthalate); pentaerythritol tetranitrate PS photoelectron spectroscopy; polystyrene peth petroleum ether ps picosecond PEX crosslinked polyethylene PSD photon stimulated desorption PF phenol-formaldehyde resin psi pounds per square inch pf power factor psia pounds per square inch absolute PFOA perfluorooctanoic acid psig pounds per square inch gage pg picogram PT perturbation theory Ph phenyl pt pint pH negative log of hydrogen ion concentration PTFE poly(tetrafluoroethylene) Phe phenylalanine PTME poly(tetramethylene terephthalate) PhIP 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine PTMS propyltrimethoxysilane PHPMS pulsed high pressure mass spectrometry PTP p-terphenyl Scientific Abbreviations, Acronyms, and Symbols 2-39
PTU phenylthiourea rem roentgen equivalent man PU polyurethane REMPI resonance-enhanced multiphoton ionization Pu purine REPE resonance energy per electron PVA poly(vinyl alcohol) RF radiofrequency PVAc poly(vinyl acetate) RGA residual gas analyzer PVC poly(vinyl chloride) Rha rhamnose PVD physical vapor deposition RHEED reflection high-energy electron diffraction PVDC poly(vinylidene chloride) RHF restricted Hartree-Fock (theory) PVDF poly(vinylidene fluoride) RI resonance ionization PVF poly(vinyl fluoride) RIA radioimmunoassay PVK poly(vinyl carbazole) Rib ribose PVME poly(methyl vinyl ether) Ribulo ribulose PVOH poly(vinyl alcohol) rms root-mean-square PVP poly(vinyl pyrrolidone) RNA ribonucleic acid PVT pressure-volume-temperature RNase ribonuclease Py pyrimidine ROHF restricted open shell Hartree-Fock PyMS pyrolysis mass spectrometry ROM read only memory p.z.c. point of zero charge ROMP ring opening metathesis polymerization Q electric charge; heat; partition function; quadrupole ROP ring opening polymerization moment; radiant energy; vibrational normal coordinate; RPA random phase approximation glutamine q electric field gradient; flow rate; heat; wave vector RPH reaction path Hamiltonian (phonons) RPLC reversed-phase liquid chromatography QCD quantum chromodynamics rpm revolutions per minute QCI quadratic configuration interaction rps revolutions per second QCT quasi-classical trajectory (method) RRK Rice-Ramsperger-Kassel (theory) QED quantum electrodynamics RRKM Rice-Ramsperger-Kassel-Marcus (theory) Q.E.D. quod erat demonstrandum (which was to be proved) rRNA ribosomal RNA QIT quadrupole ion trap RRS resonance Raman spectroscopy QMRE quantum mechanical resonance energy RS Raman spectroscopy QMS quadrupole mass spectrometry RSC reaction-solution calorimetry QSAR quantitative structure-activity relations Ry rydberg QSO quasi-stellar object S siemens; serine qt quart S area; entropy; probability current density; Poynting quad RVBESJMMJPO#56 t18 joules) vector; symmetry coordinate; spin angular momentum Qui quinovose s second; solid (phase) q.v. quod vide (which you should see) s path length; spin angular momentum; symmetry number; sedimentation coefficient; solubility; R roentgen; arginine; alkyl radical (in chemical formulas) symmetrical (as stereochemical descriptor) °R degree Rankine SAED selected area electron diffraction R electrical resistance; gas constant; molar refraction; SALC symmetry adapted linear combinations Rydberg constant; coefficient of multiple correlation SALI surface analysis by laser ionization r reaction (as in Δ H) r SAM scanning Auger microscopy r position vector; radius SAMS self-assembled monolayers RA right ascension SANS small angle neutron scattering rad radian SAR structure-activity relationship RAIRS reflection-absorption infrared spectroscopy Sar sarcosine RAM random access memory sat, satd saturated RBS Rutherford back scattering SAXS small angle x-ray scattering Rbu, Rul ribulose SB styrene butadiene copolymer RCI ring current index SBS styrene butadiene styrene block copolymer RDA rubidium dihydrogen arsenate Sc Schmidt number RDS rate determining step SC spin-coupled (method) RDX Royal Demolition Explosive (hexahydro-1,3,5-trinitro- 1,3,5-triazine) SCD state correlation diagram Re real part SCE saturated calomel electrode RE resonance energy SCF self-consistent field (method); supercritical fluid RED radial electron distribution SCP single cell protein REELS reflection electron energy loss spectroscopy SCR silicon-controlled rectifier REM reflection electron microscopy SCRF self-consistent reaction field (method) 2-40 Scientific Abbreviations, Acronyms, and Symbols sd standard deviation STM scanning tunneling microscopy SDA sulfadiazine STO Slater-type orbital SDW spin density wave STP standard temperature and pressure SE strain energy sub, subl sublimes; sublimation SEBS styrene ethylene butylene styrene block copolymer Suc, Sac sucrose SEC size exclusion chromatography Sur thiouracil sec secant; second Sv sievert sec secondary (in chemical name) SWIFT stored waveform inverse Fourier transform SECSY spin-echo correlated spectroscopy T tesla; tera (SI prefix for 1012); threonine Sed sedoheptulose T kinetic energy; period; term value; temperature SEELFS surface extended energy loss fine structure (thermodynamic); torque; transmittance t metric tonne; triton SEM scanning electron microscopy; standard error of the mean t Celsius temperature; thickness; time; transport number sepn separation TAC time-to-amplitude converter Ser serine TAI International Atomic Time SERS surface-enhanced Raman spectroscopy Tal talose SET single electron transfer tan tangent SEXAF surface extended x-ray absorption fine structure tanh hyperbolic tangent SFC supercritical fluid chromatography Taps 3-{[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]amino}-1- Sh Sherwood number propanesulfonic acid TBE 1,1,2,2-tetrabromoethane Shy thiohypoxanthine TBP tributyl phosphate SI International System of Units; surface ionization TC titration calorimetry SID surface-induced dissociation TCA trichloroacetic acid SILAR successive ionic layer adsorption and reaction TCB, 2,3,6-trichlorobenzoic acid SIM selected ion monitoring TCBA SIMS secondary-ion spectroscopy TCE trichloroethylene sin sine TCG Geocentric Coordinated Time sinh hyperbolic sine TCNE tetracyanoethylene SIPN semi-interpenetrating polymer network TCNQ tetracyanoquinodimethane SIS styrene isoprene styrene block copolymer TCP tricresyl phosphate SLAM scanning laser acoustic microscopy TCSCF two configuration self-consistent field SLUMO second lowest unoccupied molecular orbital TDA toluene-2,4-diamine SMILES simplified molecular input line entry system TDI toluene diisocyanate SMMA styrene methyl methacrylate copolymer tDNA transfer DNA SMO semiempirical molecular orbital TE transverse electric SMOW Standard Mean Ocean Water (Vienna) TEA triethanolamine; triethylamine SNMS sputtered neutral mass spectroscopy TED transferred electron device; transmission electron Sno thiouridine diffraction TEDA triethylenediamine SNU solar neutrino unit TEELS transmission electron energy loss spectroscopy SOJT second-order Jahn-Teller (effect) TEM transverse electromagnetic; transmission electron sol soluble; solution microscope soln, sln solution temp temperature SOMO singly occupied molecular orbital TEO thermoplastic elastic olefin Sor sorbose TEPP tetraethyl pyrophosphate sp gr specific gravity tert tertiary (in chemical name) SPM scanned probe microscopy Tes 2-{[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]amino}-1- SPST single-pulse shock tubes propanesulfonic acid TFD Thomas-Fermi-Dirac (method) sq square TFE tetrafluoroethylene Sr Strouhal number TGA thermogravimetric analysis sr steradian Thd ribosylthymine Srd 6-thioinosine THEED transmission high energy electron diffraction SSMS source spark mass spectroscopy theor theoretical St stoke thf, THF tetrahydrofuran St Stanton number THQ 1,2,3,4-tetrahydroquinoline std, stnd standard (state) Thr threonine STEL short-term exposure limit Thy thymine STEM scanning transmission electron microscope TI thermal ionization Scientific Abbreviations, Acronyms, and Symbols 2-41
TIPA triisopropanolamine UT universal time TL thermoluminescence UTC coordinated universal time TLC thin-layer chromatography UTP uridine 5’-triphosphate TLV threshold limit value UV ultraviolet TM transverse magnetic V volt; valine TMAB tetrabutylammonium bromide V electric potential; potential energy; volume TMAO trimethylamine oxide v reaction rate; specific volume; velocity; vibrational TMCP tri-m-cresyl phosphate quantum number; vicinal (as chemical descriptor) v/v volume per volume (volume of solute divided by volume TMEDA N,N,N’,N’-tetramethyl-1,2-ethanediamine of solution, expressed as percent) TMMV threshold molecular weight value VA vinyl acetate, vanillic acid TMS tetramethylsilane Val valine TNA 2,4,6-trinitroaniline vap vaporization TNB 1,3,5-trinitrobenzene VAT vibration assisted tunneling TNM tetranitromethane VB valence band; valence bond (theory) TNT 2,4,6-trinitrotoluene VCD vibrational circular dichroism TOCP tri-o-cresyl phosphate VDW van der Waals interaction TOF turnover frequency VHF very high frequency TOF-MS time-of-flight mass spectrometer vic vicinal (on adjacent carbon atom) tol tolyl VIS visible region of the spectrum TON turnover number vit vitreous (phase) TOPO trioctylphosphine oxide VLDPE very low density polyethylene Torr torr (pressure unit) VLPP very low pressure pyrolysis TOTP tri-o-tolyl phosphate VMA vanilmandelic acid TPE thermoplastic elastomer VOC volatile organic compound(s) TPTA triphenyltin acetate VOFF valence orbital force field TPTC triphenyltin chloride VPC vapor phase chromatography TRE topological resonance energy VSEPR valence shell electron-pair repulsion (method) Tre trehalose VSIP valence state ionization potential Tricine N-[2-hydroxy-1,1-bis(hydroxymethyl)ethyl]glycine VSLI very large scale integrated (circuit) Tris 2-amino-2-(hydroxymethyl)-1,3-propanediol VSMOW Vienna Standard Mean Ocean Water TRMC time-resolved microwave conductivity VTCS vinyltrichlorosilane tRNA transfer RNA VUV vacuum ultraviolet Trp tryptophan W watt; tryptophan trs transition W radiant energy; statistical weight; work TS transition state w energy density; mass fraction; velocity; work TSS transition state spectroscopy w/v weight per volume (mass of solute divided by volume of TST generalized transition-state theory solution, usually expressed as g/100 mL) w/w weight per weight (mass of solute divided by mass of TTF tetrathiofulvalene solution, expressed as percent) Tyr tyrosine WAXS wide angle x-ray scattering U uracil (in genetic code) Wb weber U electric potential difference; internal energy We Weber number u unified atomic mass unit WKB Wentzel-Kramers-Brillouin (approximation) u Bloch function; electric mobility; velocity WLF Williams-Landel-Ferry (equation) ua astronomical unit (AU is also used) WLN Wiswesser line notation UBFF Urey-Bradley force field wt weight UDMH 1,1-dimethylhydrazine X X unit; halogen (in chemical formula) UDP uridine 5’-diphosphate X reactance UHF ultrahigh frequency; unrestricted Hartree-Fock (method) x mole fraction UHMWPE ultrahigh molecular weight polyethylene X, Xaa unspecified amino acid ULDPE ultra low density polyethylene XAFS x-ray absorption fine structure ULPE ultra linear polyethylene Xan xanthine UMP uridine 5’-monophosphate XANES x-ray absorption near-edge structure uns, unsym unsymmetrical (as chemical descriptor) Xao xanthosine UPS, UPES ultraviolet photoelectron spectroscopy Xle leucine or isoleucine (unspecified) Ura uracil XLPE crosslinked polyethylene Urd uridine Xlu, Xul xylulose USP United States Pharmacopeia XPS, XPES x-ray photoelectron spectroscopy 2-42 Scientific Abbreviations, Acronyms, and Symbols
XRD x-ray diffraction ζ Coriolis coupling constant; electrokinetic potential XRF x-ray fluorescence η overpotential; viscosity XRS x-ray spectroscopy κ compressibility; conductivity; magnetic susceptibility; Xyl xylose molar absorption coefficient λ absolute activity; radioactive decay constant; thermal 24 Y yotta (SI prefix for 10 ); tyrosine conductivity; wavelength Y admittance; Planck function; Young’s modulus Λ angular momentum; ionic conductivity y yocto (SI prefix for 10–24) N muon; micro (SI prefix for 10–6) y mole fraction for gas (when x refers to liquid phase) μ chemical potential; electric dipole moment; electric y, yr year mobility; friction coefficient; Joule-Thompson coefficient; magnetic dipole moment; mobility; YAG yttrium aluminum garnet permeability yd yard NF microfarad YIG yttrium iron garnet Ng microgram Z zetta (SI prefix for 1021); glutamine or glutamic acid Nm micrometer (unspecified) Ns microsecond Z atomic number; compression factor; collision number; impedance; partition function; zusammen (cis- O frequency; kinematic velocity; stoichiometric number ν configuration) e neutrino –21 z zepto (SI prefix for 10 ) ν wavenumber z charge number (of an ion); collision frequency factor Π osmotic pressure; Peltier coefficient ZDO zero differential overlap Q pion ZINDO Zerner’s INDO method ρ density; reflectance; resistivity ZPE, ZPVE zero point vibrational energy σ electrical conductivity; cross section; normal stress; ZULU Greenwich mean time shielding constant (NMR); Stefan-Boltzmann constant; B alpha particle surface tension; standard deviation τ transmittance; chemical shift; shear stress; relaxation α absorption coefficient; degree of dissociation; electric time polarizability; expansion coefficient; fine structure Φ magnetic flux; potential energy; radiant power; work constant function C beta particle φ electrical potential; fugacity coefficient; osmotic β reciprocal temperature parameter (= 1/kT) coefficient; quantum yield; wavefunction χ H photon; gamma (obsolete mass unit = Ng) magnetic susceptibility χ electric susceptibility γ activity coefficient; conductivity; magnetogyric ratio; e mass concentration; ratio of heat capacities; surface Z wavefunction tension Ω ohm Γ Grüneisen parameter; level width; surface concentration Ω axial angular momentum; solid angle Δ inertial defect; mass excess ω circular frequency; angular velocity; harmonic vibration δ chemical shift; Dirac delta function; Kronecker delta; loss wavenumber; statistical weight angle ε emittance; Levi-Civita symbol; linear strain; molar absorption coefficient; permittivity