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Electron–Electron interaction energy in homonuclear diatomic molecules
Author(s) -
Piccitto G.,
Pucci R.,
March N. H.,
Grassi A.
Publication year - 1989
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.560360407
Subject(s) - homonuclear molecule , diatomic molecule , electron , atomic physics , chemistry , potential energy , molecule , physics , quantum mechanics
The derivative of the electron–electron potential energy U ee with respect to internuclear separation R is studied for light homonuclear diatomic molecules at equilibrium. It is readily related to nuclear–nuclear potential energy U nn , the force constant K , and the electron–nuclear potential energy U en . An approximate expression, based on the simplest form of density functional theory, is then used to eliminate dU en / dR | Re . The result thus obtained for dU ee / dR | Re transcends an earlier proposal of Kryachko by including a term 2/3 R e K , with K the force constant. Numerical tests at SCF–RHF level are presented for nine homonuclear diatomic molecules.