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Principles for a direct SCF approach to LICAO – MO ab ‐ initio calculations
Author(s) -
Almlöf J.,
Faegri K.,
Korsell K.
Publication year - 1982
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.540030314
Subject(s) - ab initio , chemistry , computational chemistry , electron , ab initio quantum chemistry methods , minicomputer , physics , molecule , computer science , quantum mechanics , organic chemistry , operating system
The principles and structure of an LCAO ‐ MO ab ‐ initio computer program which recalculates all two‐electron integrals needed in each SCF iteration are formulated and discussed. This approach—termed “direct SCF ”—is found to be particularly efficient for calculations on very large systems, and also for calcuations on small and medium‐sized molecules with modern minicomputers. The time requirements for a number of sample calculations are listed, and the distribution of two‐electron integrals according to magnitude is investigated for model systems.