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Ab initio calculations on large molecules using molecular fragments. Generalization of the molecular fragment basis at the minimum basis set level
Author(s) -
Spangler Dale,
Christoffersen Ralph E.
Publication year - 1980
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.560170605
Subject(s) - basis (linear algebra) , basis set , sto ng basis sets , gaussian , generalization , series (stratigraphy) , computational chemistry , chemistry , statistical physics , mathematics , geometry , physics , mathematical analysis , linear combination of atomic orbitals , density functional theory , paleontology , biology
By determining basis set parameters in molecular environments using other criteria than total energy, it is shown that a generalization of the molecular fragment basis can be obtained in which calculated geometric and electronic structural properties are predicted substantially better than with other basis sets of similar size. As a first step in the development of a series of basis sets having successively greater flexibility and accuracy, several single‐zeta basis sets are created, using a two‐Gaussian contraction for each basis orbital. The best of these basis sets produced calculated geometric and electronic properties for a series of molecules that model a wide variety of organic molecules that are of better accuracy than the corresponding STO ‐2G basis, and similar in most cases to STO ‐3G. In addition, the basis set is shown to be applicable in either a Cartesian Gaussian basis or a floating spherical Gaussian basis.