TY - JOUR

T1 - Nuclear quantum effects in chemical reactions via higher-order path-integral calculations

AU - Engel, Hamutal

AU - Eitan, Reuven

AU - Azuri, Asaf

AU - Major, Dan Thomas

N1 - Publisher Copyright:
© 2015 Elsevier B.V. All rights reserved.

PY - 2015/4/15

Y1 - 2015/4/15

N2 - A practical approach to treat nuclear quantum mechanical effects in simulations of condensed phases, such as enzymes, is via Feynman path integral (PI) formulations. Typically, the standard primitive approximation (PA) is employed in enzymatic PI simulations. Nonetheless, these PI simulations are computationally demanding due to the large number of beads required to obtain converged results. The efficiency of PI simulations may be greatly improved if higher-order factorizations of the density matrix operator are employed. Herein, we compare the results of model calculations obtained employing the standard PA, the improved operator of Takahashi and Imada (TI), and a gradient-based forward corrector algorithm due to Chin (CH). The quantum transmission coefficient is computed for the Eckart potential while the partition functions and rate constant are computed for the H2 + H hydrogen transfer reaction. These potentials are simple models for chemical reactions. The study of the different factorization methods reveals that in most cases the higher-order action converges faster than the PA and TI approaches, at a moderate computational cost.

AB - A practical approach to treat nuclear quantum mechanical effects in simulations of condensed phases, such as enzymes, is via Feynman path integral (PI) formulations. Typically, the standard primitive approximation (PA) is employed in enzymatic PI simulations. Nonetheless, these PI simulations are computationally demanding due to the large number of beads required to obtain converged results. The efficiency of PI simulations may be greatly improved if higher-order factorizations of the density matrix operator are employed. Herein, we compare the results of model calculations obtained employing the standard PA, the improved operator of Takahashi and Imada (TI), and a gradient-based forward corrector algorithm due to Chin (CH). The quantum transmission coefficient is computed for the Eckart potential while the partition functions and rate constant are computed for the H2 + H hydrogen transfer reaction. These potentials are simple models for chemical reactions. The study of the different factorization methods reveals that in most cases the higher-order action converges faster than the PA and TI approaches, at a moderate computational cost.

KW - Forward corrector algorithm

KW - Nuclear quantum effects

KW - Path integral

KW - Tunneling

UR - http://www.scopus.com/inward/record.url?scp=84929087061&partnerID=8YFLogxK

U2 - 10.1016/j.chemphys.2015.01.001

DO - 10.1016/j.chemphys.2015.01.001

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SN - 0301-0104

VL - 450-451

SP - 95

EP - 101

JO - Chemical Physics

JF - Chemical Physics

ER -