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Comparative study of unconventional 1 s basis functions for the 1 Σ g + ground state of H 2 and He 2 ++
Author(s) -
Leclerc JeanClaude
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.560100307
Subject(s) - wave function , atomic orbital , slater type orbital , gaussian , sto ng basis sets , ellipsoid , ground state , basis set , function (biology) , basis (linear algebra) , physics , basis function , mathematical analysis , quantum mechanics , type (biology) , molecular orbital , atomic physics , mathematical physics , mathematics , molecular orbital theory , geometry , molecule , geology , astronomy , evolutionary biology , biology , electron , paleontology
We investigated various nonstandard 1 s basis functions (generalized Slater‐Gaussian, ellipsoidal Gaussian, floating spherical and ellipsoidal Gaussian, rational function, Hulthén approximation, two‐Slater‐type orbital, generalized Guillemin–Zener function, and various noninteger‐ n elliptical orbitals) for approximating the 1 Σ g +ground state of H 2 and He 2 ++ . A CI trial wave‐function including Σ g ‐type MO's is adopted and molecular integrals are evaluated numerically. The energy improvement on the 1 s STO is small except for noninteger‐ n orbitals which closely approach the “ SCF limit”.