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Variational‐Perturbation theory in the LCAO‐MO method for closed‐shell molecules
Author(s) -
Malykhanov Yu. B.
Publication year - 1982
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.560210205
Subject(s) - open shell , excited state , superposition principle , wave function , perturbation (astronomy) , atomic orbital , perturbation theory (quantum mechanics) , hartree–fock method , variational principle , density matrix , variational method , molecule , physics , quantum mechanics , atomic physics , classical mechanics , quantum , electron
Using the variational principle, equations have been obtained for density matrix of molecules with the external perturbation of the common type present. The perturbed wave function was taken as a superposition of the ground and single‐excited configurations made of the Hartree‐Fock molecular spin orbitals. On the basis of these equations a series of variants of static perturbation theory have been worked out for the ground and excited states of closed‐shell molecules.