Monte Carlo explicitly correlated second-order many-body perturbation theory
| Autor: | Alexander E. Doran, Jinmei Zhang, Cole M. Johnson, So Hirata, Edward F. Valeev |
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| Rok vydání: | 2016 |
| Předmět: |
Physics
010304 chemical physics Geminal Stochastic process Monte Carlo method Ab initio General Physics and Astronomy 01 natural sciences Ab initio quantum chemistry methods Quantum mechanics 0103 physical sciences Dynamic Monte Carlo method Physical and Theoretical Chemistry 010306 general physics Basis set Monte Carlo molecular modeling |
| Zdroj: | The Journal of Chemical Physics. 145:154115 |
| ISSN: | 1089-7690 0021-9606 |
| DOI: | 10.1063/1.4964854 |
| Popis: | A stochastic algorithm is proposed and implemented that computes a basis-set-incompleteness (F12) correction to an ab initio second-order many-body perturbation energy as a short sum of 6- to 15-dimensional integrals of Gaussian-type orbitals, an explicit function of the electron-electron distance (geminal), and its associated excitation amplitudes held fixed at the values suggested by Ten-no. The integrals are directly evaluated (without a resolution-of-the-identity approximation or an auxiliary basis set) by the Metropolis Monte Carlo method. Applications of this method to 17 molecular correlation energies and 12 gas-phase reaction energies reveal that both the nonvariational and variational formulas for the correction give reliable correlation energies (98% or higher) and reaction energies (within 2 kJ mol−1 with a smaller statistical uncertainty) near the complete-basis-set limits by using just the aug-cc-pVDZ basis set. The nonvariational formula is found to be 2–10 times less expensive to evaluate t... |
| Databáze: | OpenAIRE |
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