### Abstract

A method for calculating the quantum canonical rate constant of chemical reactions in a many body system by means of a short-time flux autocorrelation function combined with a maximum entropy numerical analytic continuation scheme is presented. The rate constant is expressed as the time integral of the real-time flux autocorrelation function. The real-time flux autocorrelation function is evaluated for short times fully quantum mechanically by path integral Monte Carlo simulations. The maximum entropy approach is then used to extract the rate from the short real-time flux autocorrelation data. We present two numerical tests, one for proton transfer in harmonic dissipative environments in the deep tunneling regime and the other for the two-level model of primary charge separation in the photosynthetic reaction center. The results obtained using the flux autocorrelation data up to the time of no more than βℏ are in excellent agreement with the exact quantum calculation over a wide range of parameters including even the tunneling regime.

Original language | English |
---|---|

Pages (from-to) | 2824-2833 |

Number of pages | 10 |

Journal | Journal of Physical Chemistry A |

Volume | 105 |

Issue number | 12 |

Publication status | Published - 2001 Mar 29 |

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### All Science Journal Classification (ASJC) codes

- Physical and Theoretical Chemistry

### Cite this

*Journal of Physical Chemistry A*,

*105*(12), 2824-2833.

}

*Journal of Physical Chemistry A*, vol. 105, no. 12, pp. 2824-2833.

**Quantum rate constants from short-time dynamics : An analytic continuation approach.** / Sim, Eun Ji; Krilov, Goran; Berne, B. J.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Quantum rate constants from short-time dynamics

T2 - An analytic continuation approach

AU - Sim, Eun Ji

AU - Krilov, Goran

AU - Berne, B. J.

PY - 2001/3/29

Y1 - 2001/3/29

N2 - A method for calculating the quantum canonical rate constant of chemical reactions in a many body system by means of a short-time flux autocorrelation function combined with a maximum entropy numerical analytic continuation scheme is presented. The rate constant is expressed as the time integral of the real-time flux autocorrelation function. The real-time flux autocorrelation function is evaluated for short times fully quantum mechanically by path integral Monte Carlo simulations. The maximum entropy approach is then used to extract the rate from the short real-time flux autocorrelation data. We present two numerical tests, one for proton transfer in harmonic dissipative environments in the deep tunneling regime and the other for the two-level model of primary charge separation in the photosynthetic reaction center. The results obtained using the flux autocorrelation data up to the time of no more than βℏ are in excellent agreement with the exact quantum calculation over a wide range of parameters including even the tunneling regime.

AB - A method for calculating the quantum canonical rate constant of chemical reactions in a many body system by means of a short-time flux autocorrelation function combined with a maximum entropy numerical analytic continuation scheme is presented. The rate constant is expressed as the time integral of the real-time flux autocorrelation function. The real-time flux autocorrelation function is evaluated for short times fully quantum mechanically by path integral Monte Carlo simulations. The maximum entropy approach is then used to extract the rate from the short real-time flux autocorrelation data. We present two numerical tests, one for proton transfer in harmonic dissipative environments in the deep tunneling regime and the other for the two-level model of primary charge separation in the photosynthetic reaction center. The results obtained using the flux autocorrelation data up to the time of no more than βℏ are in excellent agreement with the exact quantum calculation over a wide range of parameters including even the tunneling regime.

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M3 - Article

AN - SCOPUS:0035967406

VL - 105

SP - 2824

EP - 2833

JO - Journal of Physical Chemistry A

JF - Journal of Physical Chemistry A

SN - 1089-5639

IS - 12

ER -