A unified framework for quantum activated rate processes .1. General theory
A unified framework for quantum activated rate processes .1. General theory
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DOI：
10.1063/1.471980
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发表时间：
1996-10-22
影响因子：
4.4
通讯作者：
Voth, GA
中科院分区：
文献类型：
--
作者：
Cao, JS;Voth, GA
它表明，几个现有的量子反应速率理论可以统一在一个单一的数学框架。这些理论包括高温抛物势垒近似、瞬子近似和路径积分量子过渡态理论。特别是，它示出的量子反应通量可以近似为一个简单的频率因子乘以势垒配分函数的虚部的产品。后一项来自势垒区配分函数的最速下降解，而前因子可以解释为稳态势垒轨迹的频率。重要的是，分析引入虚时间费曼路径质心变量的量子激活速率常数的表达式中的先验的方式。本理论框架还允许在交叉温度附近的量子激活速率问题的分析处理，并在扩展维量子力学空间的傅立叶路径模式的鞍点分析的泛化。(C)1996年美国物理学会。
It is shown that several existing quantum reaction rate theories can be unified around a single mathematical framework. These theories include the high temperature parabolic barrier approximation, the instanton approach, and the path integral quantum transition state theory. In particular, it is shown that the quantum reactive flux can be approximated as a product of a simple frequency factor times the imaginary part of the barrier partition function. The latter term arises from the steepest descent solution to the partition function in the barrier region, while the prefactor can he interpreted as the frequency of the stationary barrier trajectory. Importantly, the analysis introduces the imaginary time Feynman path centroid variable into the expression for the quantum activated rate constant in an a priori way. The present theoretical framework also allows for an analytical treatment of the quantum activated rate problem in the vicinity of the crossover temperature, and for a generalization of the saddle point analysis in an extended-dimensional quantum mechanical space of the Fourier path modes. (C) 1996 American Institute of Physics.