Premium
Explicitly correlated configuration interaction studies using spherical Gaussians. II. Exploratory studies on LiH
Author(s) -
Karunakaran K. M.,
Christoffersen Ralph E.
Publication year - 1982
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.560220103
Subject(s) - wave function , gaussian , configuration interaction , ab initio , electronic correlation , basis (linear algebra) , hartree–fock method , atomic orbital , full configuration interaction , atomic physics , ground state , fock space , physics , chemistry , quantum mechanics , molecule , geometry , mathematics , excited state , electron
Ab initio self‐consistent‐field and configuration interaction studies have been carried out on the ground state of the LiH molecule at its equilibrium distance. Floating spherical Gaussian basis orbitals ( FSGO ) were employed, along with spherical Gaussian correlation factors, using the procedure described in the preceding paper. A near‐Hartree–Fock function was found using only 13 FSGO . Exploratory configuration interaction studies recovered approximately 73% of the inner shell correlation energy and approximately 56% of the total correlation energy with five configurations plus the Hartree–Fock configuration. These studies indicate that, by using spherical Gaussian correlation factors, direct introduction of interelectronic coordinates into trial wave functions can be accomplished for molecular systems. It was also shown that correlating configurations need not utilize the full Hartree–Fock basis, but may use substantially smaller bases and still recover correlation energy effectively. Finally, the results indicate that, in spite of their improper cusp behavior, FSGOS and spherical Gaussian correlation factors can be used for construction of high accuracy wave functions.