I  U  P  A  C

News & Notices

Organizations & People

Standing Committees



..By Year
..By Division
..Other Committees




Links of Interest

Search the Site

Home Page




Pure Appl. Chem., Vol. 71, No. 10, pp. 1919-1981, 1999

Appendix. Glossary of acronyms of terms used in theoretical organic chemistry

[A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L]
[M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Y] [Z]

AIM Atoms In Molecules - method of topological analysis of distribution of electron density.
AM1 Austin Model 1 - semiempirical method of quantum chemistry [DEWAR and ZOEBISCH (1985)].
AO Atomic Orbital.
AOM Angular Overlap Model.
ASE Aromatic Stabilization Energy.
BDE Bond Dissociation Energy.
BEBO Bond Energy Bond Order method.
B3LYP Becke Lee, Yang and Parr hybrid functional which defines the exchange functional as a linear combination of HF, local and and gradient-corrected exchange terms [BECKE (1988), LEE (1988)].
BO Born - Oppenheimer approximation.
BRE Bond Resonance Energy.
BSSE Basis Set Superposition Error.
CAS Complete Active Space.
CASPT Complete Active Space Perturbation Theory.
CASPT2 CASPT based method with second order perturbation theory [ANDERSON (1992)].
CASSCF Complete-Active-Space SCF method of solution of the electronic Schrödingerequation [ROOS (1980)].
CBS Complete Basis Set of orbitals.
CC Coupled Cluster.
CCSD(T) Coupled Cluster Single, Double (Triple) excitations.
CDW Charge Density Waves.
CEPA Coupled Electron-Pair Approximation.
CHF Coupled HF method.
CI Configuration Interaction.
3 x 3 CI CI for all three possible singlet configurations in the two-electron two-orbital model.
CID CI, Double excitations only,
Collision Induced Dissociation.
CIDNP Chemically Induced Dynamic Nuclear Polarization.
CIS CI, Single excitations only.
CISD Single and Double excitations, single reference CI method.
CISDT CISD plus Triple excitations.
CISDQ (or QCISD) CISD plus Quadruple excitations, see also QCISD.
CISDTQ CISD plus triple and quadruple excitations.
CMO Canonical Molecular Orbital.
CNDO Complete Neglect of Differential Overlap.
CNDO/2 Complete Neglect of Differential Overlap, semiempirical method of quantum chemistry with paramerization according to Pople & Segal [POPLE and SEGAL (1966)].
CNDO/S Complete Neglect of Differential Overlap/ Spectroscopic parametrization  according to Del Bene & Jaffe [DEL BENE (1968)].
COOP Crystal Orbital Overlap Population.
CSD Cambridge Structural Database.
CT Charge Transfer.
DE Delocalization Energy.
DFT Density Functional Theory.
DIM Diatomics In Molecules.
DNMR Dynamic NMR spectroscopy
DOS Density of States.
DRE Dewar Resonance Energy.
DRP Dynamic Reaction Path.
DZ Double-Zeta type of basis set.
DZP DZ plus Polarization function basis set.
EA Electron Affinity.
EAN Effective Atomic Number rule.
ECP Effective Core Potential.
EFF Empirical Force Field.

Extended Hückel Molecular Orbital, semiempirical method of quantum chemistry [HOFFMANN (1963)].

EHT Extended Hückel Theory.
EM Effective Molarity.
EPR Electron Paramagnetic Resonance.
ESR Electron Spin Resonance spectroscopy.
ET Electron Transfer.
EXAFS Extended X-ray Absorption Fine Structure spectroscopy [BERTRAGNOLI (1994)]
FSGO Floating Spherical Gaussian Orbitals.
G1 Gaussian1, a method for ab initio calculations based on the MP4/6-311G(d.p)/MP2/6-31G(d) scheme with corrections of the incompletness of the basis through inclusion of diffuse functions and extra d- and f- functions for non-hydrogen atoms [POPLE, HEAD-GORDON, et. al. (1989)].
G2 Gaussian 2, a method for ab initio calculations that improves the G1 methodology byincluding corrections for the larger 6-311+G(3df, 2p) basis set and providing empirical correction for the number of valence electron pairs. The theory corresponds effectively to calculations at the QCISD(T)/6-311 + G(3df, 2p) level with zero-point vibrational energy (ZPE) and higher level correlations [CURTISS, RAGHAVACHARI, et. al. (1991)].
GIAO Gauge Invariant Atomic Orbitals.

Gaussian - Type Orbitals.

GVB Generalized Valence Bond method.
GVB-CI GVB plus CI method.
HAM Hydrogenic Atoms in Molecules method. HAM/N (N=1,2,3) - versions of the method [LINCHOLM (1985)].
HE Half Electron method.
HF Hartree-Fock method.
HMO Hückel Molecular Orbital.
HOMO Highest Occupied Molecular Orbital.
HOMAS Harmonic Oscillator Model of Aromatic Stabilization.
HOSE Harmonic Oscillator Stabilization Energy.
HRE Hückel Resonance Energy.
HSE Homodesmotic Stabilization Energy.
HSRE Hess-Schaad Resonance Energy.
ICCI Internally Contracted CI method.
IEPA Independent Electron-Pair Approximation.
IGLO Individual Gauge for Localized Orbitals.
IRC Intrinsic Reaction Coordinate.
INDO Intermediate Neglect of Differential Overlap. A semiempirical method of quantum  chemistry [POPLE, BEVERIDGE, and DOBOSH (1967)].
INDO/S Intermediate Neglect of Differential Overlap/ Spectroscopic parametrization [ANDERSON, EDWARDS, and ZERNER (1986)].
INDO/S - CI Intermediate Neglect of Differential Overlap/ Spectroscopic parametrization accounting for Configuration Interaction [FOX (1993)].
IP Ionization Potential.
ISE Isodesmic Stabilization Energy.
JT Jahn - Teller effect.
KIE Kinetic Isotope Effect.
LCAO MO Linear Combination of Atomic Orbitals representation of Molecular Orbitals.
LDA Local Density Approximatiom in DFT.
LE Localization Energy.
LFER Linear Free Energy Relationships.
LFSE Linear Field Stabilization Energy.
LMO Localized Molecular Orbital.
LORG Localized Orbital, Localized Origin method.
LUMO Lowest Unoccupied Molecular Orbital.
MBPT(n) Many-Body Perturbation Theory of nth Order.
MC Monte Carlo method.
MC SCF MultiConfiguration SCF theory.
MC-IGLO MultiConfiguration IGLO.
MCPF Modified-Coupled-Pair-Functional.
MD Molecular Dynamics method.
MEP Molecular Electrostatic Potential.
MERP Minimum Energy Reaction Path.
MIDI-N MIDdle size split-valence type contracted GTO basis set (N = 1-4).
MINDO Modified INDO, MINDO/N (N = 1,2,3) - versions of the semiempirical method of quantum chemistry [DEWAR, BINGHAM, and LO (1975)].
MINI-N MINImal-type contracted GTO basis set (N = 1-4).
MM Molecular Mechanics.
MM2 Molecular Mechanics force field, 2d version of the parametric set and the program using molecular mechanics [ALLINGER (1977)].
MM3 Molecular Mechanics force field, 3d version of the parametric set and the computer program [ALLINGER,CHEN, and RAHMAN (1993)].
MMX Molecular Mechanics empirical force field [GAJEWSKII (1990)].
MNDO Modified Neglect of Diatomic Overlap. A semiempirical method of quantum chemistry [DEWAR and THIEL (1977)].
MNDOC MNDO method with a perturbative treatment of electron Correlation [THIEL (1981)].
MO Molecular Orbital.
MOVB MO VB theory.
MPA Mulliken Population Analysis.
MPN (N = 2-4) MØller-Plesset perturbation theory of order N for electron correlation [MØLLER (1934)].
MP2/6-31G*//HF/6-31G* Example of abridged notation to specify the type of level used in a givencalculation : the MP2 theory and of the 6-31G* basis set, at the geometry optimized at HF/6-31G* method.
MRD Multireference Double substitution, method of.
MRDCI MRD with inclusion of CI.
N-31G, etc. Pople's basis set. Notations of this basis sets like N-ijG or N-ijkG should be encoded as follows: N - number of Gaussian primitives (GTOs) for the inner shells; ij or ijk - number of Gaussian primitives for contractions in the valence shell. The ij notations correspond to basis sets of valence DZ quality and ijk notations indicate split valence sets of triple zeta (TZ) quality. N-ijG* denotes a polarized basis set augmented with d type functions on heavy atoms only ; N-ijG** (or N-ijG(d,p) - basis set with p-functions on hydrogen atoms.
N-31+G(d), etc#. Pople's basis set with diffuse function. For example, 6-311+G(2df,2pd) putting 2d functions and 1f function on heavy atoms (plus diffuse functions), and 2p functions and 1d function on hydrogens.
#) According to the IUPAC recommendation, the actual construction of the basis sets for each atom should be specified as (abc..., ghi..., lm..., o...), where a is the number of primitives usually GTOs) in the first contracted s function, b is the number of primitives in the second contracted s function, etc., g is the number of primitives in the first contracted p function , l is the number of primitives in thecontracted d function, and o is the number of primitives in the first contracted f function. Thus, a 6-31+G* basis for carbon should be designated as (6311, 311, 1)
"Guidelines for the Presentation of Quantum Mechanical Computational Data in Organic Chemistry".Prepared for publication by Albright & Halevi
[ALBRIGHT and HALEVI (1992)].
NAO Natural Atomic Orbital.
NBO Natural Bond Orbital.
NDDO Neglect of Diatomic Differential Overlap. A semiempirical method of quantum chemistry [POPLE, SANTRY, and SEGAL (1965)].
NHO Natural Hybrid Orbital.
NICS Nuclear Independent Chemical Shift.
NMR Nuclear Magnetic Resonance.
NPA Natural Population Analysis.
OCAMS Orbital Correspondence Analysis in Maximum Symmetry.
OFGF Outer Valence Green's Function method.
PA Proton Affinity.
PCILO Perturbative Configuration Interaction using Localized Orbitals method.
PCM Polarizable Continuum Model of solvation.

Potential Energy Surface.
Photoelectron Spectroscopy.

PLM Principle of Least Motion.
PM3 Parametric Method 3 - a semiempirical method of quantum chemistry based on theMNDO scheme [STEWART (1989)].
PMO Perturbation MO theory.
PNO Pair Natural Orbitals
POAV p - Orbital Axis Vector.
PPFMO Polarized p-Frontier MO theory [HUANG (1993)].
PPP Pariser-Parr-Pople, method of.
PRDDO Partial Retention of Diatomic Differential Overlap. A semiempirical method of quantum chemistry [HALGREN (1973)].
PT Perturbation Theory.
QCI Quadratic Configuration Interaction, method of.
QCISD Quadratic CI with Single and Double excitations, see also CISD.
QCISD (T) QCISD with perturbational treatment of Triple excitations.
QCISD (TQ) QCISD with perturbational treatment of Triple and Quadruple excitations.
QMRE Quantum Mechanical Resonance Energy.
QSAR Quantitative Structure - Activity Relationships.
RCI Ring Current Index.
RE Resonance Energy.
REPE Resonance Energy Per Electron.
RHF Restricted HF theory.
ROHF Restricted Open shell HF theory.
RPH Reaction Path Hamiltonian.
RRKM Rice - Ramsperger - Kassel - Marcus theory.
SAM1 Semi-Ab-initio Model 1. Version 1 of a semiempirical method of quantum chemistry [DEWAR, JIE, and YU (1993)].
SC Spin-Coupled method.
SCD State Correlation Diagram.
SCF Self-Consistent Field, method of.
SCI-PCM Self-Consistent Isodensity Polarizable Continuum Model of solvation.
SCRF Self-Consistent Reaction Field, method of.
SDW Spin Density Wave.
SE Strain Energy.
SET Single Electron Transfer.
SINDO Symmetrically orthogonalized INDO method. SINDO1 - a version of the method [NANDA (1980)].
SOJT Second-Order Jahn - Teller effect.
SO Spin - Orbital.
SOMO Singly Occupied Molecular Orbital.
STO Slater - Type Orbital [SLATER (1930)].
STO - NG STO approximation by the sum of N (3-6) GTOs.
TCSCF Two Configuration SCF method , a special case of MC SCF.
TRE Topological Resonance Energy.
TS Transition State.
TSS Transition State Spectroscopy
UHF Unrestricted HF method.
UMNDO UHF version of MNDO.
VAT Vibration Assisted Tunnelling.
VB Valence Bond theory
VBCM Valence Bond Configuration Mixing model.
VDW van der Waals interactions.
VSEPR Valence Shell Electron-Pair Repulsion method.
VSIP Valence State Ionization Potential.
XPS X-ray Photoelectron Spectroscopy.
ZDO Zero Differential Overlap.
ZINDO Zerner’s INDO method.
ZPE Zero Point vibration Energy.
ZPVE Zero Point Vibration Energy.


[A] [B] [C] [D] [E] [F] [G] [H] [I] [J-K] [L] [M]
[N] [O] [P] [Q-R] [S] [T] [U-V] [W-Z]

> Abstract
> General remarks
> Arrangement

> Fundamental physical constants used in the glossary
> References

> Appendix. Glossary of acronyms of terms used in theoretical organix chemistry

Page last modified 22 November 2000.
Copyright © 2000 International Union of Pure and Applied Chemistry.
Questions or comments about IUPAC, please contact, the Secretariat.
Questions regarding the website, please contact Web Help.