Premium
Comparative study of semiempirical methods for calculating interactions between large molecules with an application to the actinomycin—Guanine complex
Author(s) -
Pack George R.,
Loew Gilda H.,
Yamabe Shinichi,
Morokuma Keiji
Publication year - 2009
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.560140739
Subject(s) - supermolecule , cndo/2 , chemistry , stacking , ab initio , computational chemistry , intermolecular force , ab initio quantum chemistry methods , molecule , perturbation theory (quantum mechanics) , electronic correlation , molecular physics , chemical physics , physics , quantum mechanics , organic chemistry
A comparison of semiempirical variational and perturbation calculations of intermolecular interactions is presented. The results are compared with ab initio rhf calculations, ab initio perturbation calculations, and with experiments for systems representing hydrogen bonding, electron donor‐acceptor complexes, incipient chemical reactions, and π‐π stacking interactions. The failure of CNDO supermolecule calculations is discussed. Various approaches to a perturbation scheme using CNDO wave functions are investigated and an optimal method is suggested. The calculation of the stacking interactions in the deoxyguanosine actinomycin D complex suggests that a dual charge‐transfer complex is formed. The experimental observation of two inequivalent binding sites on the actinomycin chromophore is interpreted in terms of the calculated energetics of complex formation.