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An unconventional scf method for calculations on large molecules
Author(s) -
Cremer Dieter,
Gauss JüRgen
Publication year - 1986
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.540070305
Subject(s) - basis (linear algebra) , basis set , matrix (chemical analysis) , convergence (economics) , set (abstract data type) , density matrix , mathematics , cutoff , computational chemistry , statistical physics , density functional theory , physics , chemistry , computer science , quantum mechanics , geometry , chromatography , economics , quantum , programming language , economic growth
An unconventional SCF method for calculations on large molecules with more than 100 basis functions is described. Storage problems which arise in conventional SCF schemes when storing more than 10 7 integrals are avoided by repeated calculation of integrals. The resulting increase in computational times is kept at a reasonable level by (a) improving the initial guess, (b) accelerating convergence, (c) employing a recursive construction of the Fock matrix, and (d) eliminating insignificant integrals from the calculation by a density‐weighted cutoff criterion. Sample calculations show that, compared with conventional SCF calculations, computational times increase by 25%–75% depending on the basis set and the shape of the molecule.