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A charge‐conserving approximation method for ab initio calculations
Author(s) -
Ding FuJiang,
Zhang LiangFu,
Li GuangNian
Publication year - 1989
Publication title -
acta chimica sinica english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.28
H-Index - 41
eISSN - 1614-7065
pISSN - 0256-7660
DOI - 10.1002/cjoc.19890070405
Subject(s) - ab initio , chemistry , atomic orbital , dipole , charge (physics) , basis set , molecular orbital , ab initio quantum chemistry methods , atomic physics , slater type orbital , kinetic energy , molecular orbital theory , molecule , molecular physics , computational chemistry , physics , quantum mechanics , electron , density functional theory , organic chemistry
Abstract A new method is presented for approximate ab initio calculations in quantum chemistry. It is called CCAM (charge conserving approximation method). The calculation method does not include the use of empirical parameters. We use Slater type orbitals as basis set, replacing STO's by STO‐2G functions to evaluate three‐ and four‐center integrals and making the STO‐2G two‐orbital charge distributions have the same total charge as STO. The results are presented for test calculations on five molecules. In view of these results, CCAM is better than ab initio calculations over STO‐6G in the results on total energies, kinetic energies and occupied orbital energies. In atomic populations, dipole moments and unoccupied orbital energies, CCAM is also satisfactory. We estimate that CCAM would be as fast as ab initio calculations over STO‐2G in evaluating molecular integrals.