A parallel vectorized implementation of triple excitations in CCSD(T): application to the binding energies of the AlH3, AlH2F, AlHF2 and AlF3 dimers

Alistair P. Rendell, Timothy J. Lee, Andrew Komornicki

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72 Citations (Scopus)

Abstract

An efficient method for evaluating various non-iterative estimates of connected triple excitations in coupled-cluster theory is outlined and related to a similar expression occurring in Møller-Plesset perturbation theory. The method is highly vectorized and capable of utilizing multiple processors on a shared-memory machine, leading to computational rates in excess of one billion floating-point operations per second on four processors of a CRAY Y-MP. Using the new procedure, the binding energies of the D2h diborane-type dimers of AlH3, AlH2F, AlHF2 and AlF3 have been determined to be 32, 40, 20 and 47 kcal/mol, respectively. For Al2F6, the correlation procedure includes 232 molecular orbitals and over 1.5 × 106 single and double coupled-cluster amplitudes, effectively accounting for over 2 × 109 connected triple excitations.

Original languageEnglish
Pages (from-to)462-470
Number of pages9
JournalChemical Physics Letters
Volume178
Issue number5-6
DOIs
Publication statusPublished - 5 Apr 1991
Externally publishedYes

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