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Updated: Jul 15, 2026

Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
New parallel algorithm for MP2 energy gradient calculations
Kazuya Ishimura1, Peter Pulay, Shigeru Nagase
1Department of Theoretical Molecular Science, Institute for Molecular Science, Myodaiji, Okazaki, Aichi 444-8585, Japan.
Abstract:
A new parallel algorithm has been developed for calculating the analytic energy derivatives of full accuracy second order Møller-Plesset perturbation theory (MP2). Its main projected application is the optimization of geometries of large molecules, in which noncovalent interactions play a significant role. The algorithm is based on the two-step MP2 energy calculation algorithm developed recently and implemented into the quantum chemistry program, GAMESS. Timings are presented for test calculations on taxol (C47H51NO14) with the 6-31G and 6-31G(d) basis sets (660 and 1032 basis functions, 328 correlated electrons) and luciferin (C11H8N2O3S2) with aug-cc-pVDZ and aug-cc-pVTZ (530 and 1198 basis functions, 92 correlated electrons). The taxol 6-31G(d) calculations are also performed with up to 80 CPU cores. The results demonstrate the high parallel efficiency of the program.
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