Premium
Molecular valence calculations based on stepwise approximations for orthogonality and core‐valence interactions
Author(s) -
Pakkanen Tapani A.,
Lindblad Marina,
Laitinen Risto S.
Publication year - 1986
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.560290611
Subject(s) - valence (chemistry) , atomic orbital , chemistry , orthogonality , molecule , computational chemistry , molecular physics , atomic physics , quantum mechanics , physics , mathematics , geometry , electron
An approximate method for the calculation of the electronic structure of molecules has been developed. The principal approximations involve freezing of the atomic core orbitals, description of the core‐valence interactions by density matrix expansion techniques, and the enforcement of the core‐valence orthogonality by auxiliary bases and projection operator techniques. The general principle in the approximations is their stepwise execution. Each approximation can be separately relaxed and tested for reliability. The developed computational techniques have been described. A detailed analysis for the approximations is given for LiH. Other molecular test calculations include HCl, H 2 S, H 2 Se, and H 2 S 2 molecules. The results demonstrate the suitability of the method for molecular studies.