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Constrained self‐consistent‐field wave functions with improved long‐range behavior
Author(s) -
Thakkar Ajit J.,
Koga Toshikatsu,
Matsuyama Hisashi,
Archibong Edet F.
Publication year - 1992
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.560440604
Subject(s) - multipole expansion , dipole , superposition principle , gaussian , constraint (computer aided design) , range (aeronautics) , moment (physics) , wave function , basis (linear algebra) , physics , energy (signal processing) , field (mathematics) , atomic physics , basis set , chemistry , quantum mechanics , mathematics , materials science , molecule , geometry , pure mathematics , composite material
The recent suggestion that the long‐range behavior of energy‐optimized Gaussian basis sets can be improved by augmenting them with a Gaussian chosen to satisfy a constraint involving a linearly averaged position moment is explored. Calculations indicate that the high‐order moments 〈 r k 〉, with k > 4, in He, Be, and Li − , and 〈 x k z L − k 〉, with L > 4 and k ≤ L , in H 2 are improved by the constraint, but that lower‐order moments and dipole polarizabilities are not. In H 2 , the higher moments with a given L improve by different amounts for different k , and, hence, the multipole moments do not improve. The basis‐set superposition error in HeHe and BeBe interaction energy calculations decreases if the internuclear distance is large enough. Thus, the constraint procedure improves the very long range behavior of the self‐consistent‐field wave functions. © 1992 John Wiley & Sons, Inc.