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Modified PCILO method. II. Second‐order energy and geometry of transition‐metal halides
Author(s) -
Boča R.,
Pelikán P.
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.560180603
Subject(s) - cndo/2 , chemistry , hamiltonian (control theory) , atomic physics , perturbation theory (quantum mechanics) , molecule , ion , computational chemistry , quantum mechanics , physics , mathematics , mathematical optimization , organic chemistry
The modified PCILO method, for which the use of the Rayleigh–Schrödinger many‐body perturbation theory with the Møller–Plesset type of Hamiltonian partitioning is characteristic, has been extended to energy calculations of transition metal compounds. On the CNDO /2 level of the Hamiltonian approximation the energy and geometry of the ions Cu X 4 2− , M Cl 4 2− and the molecules Cu X ( X = F, Cl, Br; M = Mn, Fe, Co, Ni, Cu) have been calculated. The comparison with MO LCAO SCF calculations ( CNDO /2– UHF ) shows that the localized bonding model used here can be regarded as a good zeroth‐order approximation describing the bonding situation in complexes of this type. The perturbation theory also provides an improvement of the harmonic force constants of the Cu X molecules with respect to the SCF level of approximation.