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An economic storage and processing method for two‐electron integrals in LCAO ‐ MO calculations
Author(s) -
Billingsley Frank P.
Publication year - 1972
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.560060405
Subject(s) - electron , scheme (mathematics) , mathematics , computer science , algorithm , physics , quantum mechanics , mathematical analysis
Abstract An economic algorithm for storing and processing two‐electron integrals arising in LCAO‐MO calculations is presented. The integrals are sorted prior to the SCF iterative scheme, classified according to equivalences in the orbital indices and finally stored on separate files that contain only integrals of one type. The novel approach of physically separating the integrals according to category is shown to be more efficient than random storage. Actual computing times for the new technique are tabulated for a representative number of molecular systems and compared with times obtained using previously reported methods.