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Many‐electron wave functions represented as naturally correlated pairs: I. Method and application to H 2 and LiH
Author(s) -
Rothenberg Stephen
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.560010652
Subject(s) - atomic orbital , wave function , molecular orbital , polyatomic ion , natural bond orbital , configuration interaction , slater type orbital , function (biology) , atomic physics , physics , computational chemistry , chemistry , electron , quantum mechanics , molecule , molecular orbital theory , evolutionary biology , biology
A computational method for generating correlated wave functions for atoms and molecules is proposed. This procedure is: (1) find the Roothaan‐Hartree‐Fock orbitals for the system; (2) transform these orbitals to localized molecular orbitals { f i }; (3) introduce the explicit correlation factor k { r 12 ) for each pair of interest by forming the correlated pair function f i (1) f i (2) k ( r 12 ), and analyze it into natural‐orbital form; and (4) perform a configuration‐interaction calculation using the configurations formed from the analysis in (3) within the separated pair approximation. This method has the advantage of giving the orbitals to be used for the calculation as well as selecting the configurations that are required. It appears that this method will find its greatest applicability in calculating the potential energy curves of polyatomic systems.