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Integral approximations on the basis of semiorthogonalized orbitals
Author(s) -
Kashiwagi Hiroshi
Publication year - 1976
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.560100111
Subject(s) - basis set , slater type orbital , atomic orbital , linear combination of atomic orbitals , molecular orbital theory , molecular orbital , sto ng basis sets , basis (linear algebra) , cubic harmonic , complete active space , localized molecular orbitals , physics , atomic physics , chemistry , electron , quantum mechanics , molecule , mathematics , geometry
Semiorthogonalized orbitals are introduced as a basis of approximate ab initio molecular calculations. The semiorthogonalized orbitals are obtained from the usual overlapping atomic orbitals by means of a generalized Löwdin transformation. The new orbitals are characterized by two features: many overlaps between them are zero, and they are close to their corresponding initial atomic orbitals. On the basis of the semiorthogonalized orbitals, a scheme of integral approximations is proposed which allows one to carry out approximate ab initio calculations with less computational efforts and thus offers a possibility to perform calculations on much bigger molecules with limited computational facilities. Results are presented for model calculations on the anthracene π‐electron system. Orbital energies and electron distribution are quite close to the rigorously calculated values.