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Adiabatic potential analysis for some carbon‐containing molecules
Author(s) -
Abarenkov I. V.,
Smelkov K. V.
Publication year - 2003
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10546
Subject(s) - chemistry , molecule , intramolecular force , radical , ion , molecular orbital , density functional theory , adiabatic process , computational chemistry , bond length , ab initio , atomic physics , physics , stereochemistry , thermodynamics , organic chemistry
Abstract In the current article, the procedure to separate a molecule into the ion radicals and bonds, proposed earlier by one of authors within the Hartree–Fock (HF) approach, is used. In this procedure the ion‐radical–occupied orbitals are defined as solutions of HF equations for ion radical in the basis of occupied molecular orbital (MO) of the whole molecule. The bond orbitals are constructed to complete the functional space span by the occupied MO of ion radicals to the functional space span by occupied MO of the whole molecule. In this approach it is easy to calculate the electron density of all ion radicals and bonds, which add up to the total electron density of the whole molecule, the densities overlap being taken into account. Hence, the adiabatic potential of the molecule is expressed as a sum of ion radicals and bonds self‐energies and of various intramolecular interaction energies. The results of ab initio adiabatic potential calculations and its decomposition for several carbon‐containing molecules, such as CH 4 , CH 3 Li, CH 3 F, and C 2 H 6 , which can be considered as two ion radicals connected by a single chemical bond, are presented here. The dependence of adiabatic potential components on the bond length is analyzed, and simple approximate equations for them are generated. In addition, the electronic structure of ion‐radical CH + 3 , common for all molecules calculated here, is considered, and its dependence on the molecular environment is analyzed. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2004