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The quality of s ‐orbitals determined by least‐squares fitting and constrained variational methods
Author(s) -
Robertson Donald D.,
Smith Vedene H.,
Simas Alfredo M.,
Thakkar Ajit J.
Publication year - 1986
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.560300602
Subject(s) - atomic orbital , basis set , cubic harmonic , basis (linear algebra) , complement (music) , quality (philosophy) , molecular orbital , slater type orbital , range (aeronautics) , chemistry , physics , atomic physics , linear combination of atomic orbitals , computational chemistry , quantum mechanics , mathematics , materials science , density functional theory , molecule , geometry , biochemistry , complementation , composite material , gene , phenotype , electron
Calculations of a wide range of position and momentum space properties of 23 orbital basis sets for atomic helium are performed to supplement our previous work. The combined results on 94 orbital basis sets are used to demonstrate that, as in the case of d ‐orbitals, the least squares error is not as discriminating as other information theoretic measures of overall quality for s ‐orbitals. Detailed comparisons suggest that constrained variation can improve the overall quality of the resulting orbital provided that the constraints are selected carefully to complement the bias inherent in the energy expectation value and the functional form of the basis functions.