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Optimal virtual orbitals to relax wave functions built up with transferred extremely localized molecular orbitals
Author(s) -
Gei Alessandro,
Fornili Arianna,
Sironi Maurizio
Publication year - 2005
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.20213
Subject(s) - molecular orbital , natural bond orbital , molecular orbital theory , atomic orbital , slater type orbital , basis set , localized molecular orbitals , linear combination of atomic orbitals , cubic harmonic , delocalized electron , chemistry , physics , atomic physics , molecule , molecular physics , electron , quantum mechanics
Extremely localized molecular orbitals (ELMOs), namely orbitals strictly localized on molecular fragments, are easily transferable from one molecule to another one. Hence, they provide a natural way to set up the electronic structure of large molecules using a data base of orbitals obtained from model molecules. However, this procedure obviously increases the energy with respect to a traditional MO calculation. To gain accuracy, it is important to introduce a partial electron delocalization. This can be carried out by defining proper optimal virtual orbitals that supply an efficient set for nonorthogonal configurations to be employed in VB‐like expansions. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 827–835, 2005