Pre-processing two-electron integrals for efficient utilization in many-electron self-consistent field calculations
✍ Scribed by Richard C. Raffenetti
- Publisher
- Elsevier Science
- Year
- 1973
- Tongue
- English
- Weight
- 382 KB
- Volume
- 20
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
A procedure for pre-processing 3 random list of two-electron integrals is descrikd. Construction of Fock-matrices with the resulting PR-file is shown to be three times faster than use of n file containing the random two-eIection integrals, indices, and a branching code.
An important rate-determining step of seifconsistent field iterations in the Roothaan Hartree-Fock scheme is the formation of the Fock matrix F. In particular the time is used largely for manipulating the unique electron-repulsion integrals, of which there are more than N4/8 in the case of N basis functions. For large bases, transformation of the atomic orbital integrals to those of a molecular symmetry-adapted basis is very time consuming and therefore, many computer programs have evolved which employ the integrals in the original atomic orbital basis. The problem to be addressed here is the efficient formation of the matrix G, where