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Toward a microscopic description of molecular electronic systems
Author(s) -
Pucci Renato,
Baldo Marcello,
Grassi Antonio,
Tomasello Pasquale
Publication year - 1980
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.560180104
Subject(s) - random phase approximation , excitation , perturbation theory (quantum mechanics) , physics , moment (physics) , statistical physics , quantum mechanics , quantum electrodynamics
Abstract The many‐body perturbation theory is reformulated within the dielectric function method presented in the preceding paper [12]. The self‐energy effects are explicitly considered. These corrections turn out to be important and are calculated to the same level of approximation as the corresponding local‐field terms. The method is at the moment applicable to π‐electron systems within the zero differential overlap approximation. Explicit calculations of the excitation energies for the benzene molecule, using different parametrizations, are presented. Comparison is made with the results obtained in the random phase approximation ( RPA ) and other schemes.