Department of Biophysics, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, New York 10461, USA.
J Chem Phys. 2011 Jan 21;134(3):034109. doi: 10.1063/1.3545978.
The recently proposed mixed quantum-classical method is extended to applications at finite temperatures. The method is designed to treat complex systems consisting of a low-dimensional quantum part (the primary system) coupled to a dissipative bath described classically. The method is based on a formalism showing how to systematically correct the approximate zeroth-order evolution rule. The corrections are defined in terms of the total quantum Hamiltonian and are taken to the classical limit by introducing the frozen Gaussian approximation for the bath degrees of freedom. The evolution of the primary system is governed by the corrected propagator yielding the exact quantum dynamics. The method has been tested on a standard model system describing proton transfer in a condensed-phase environment: a symmetric double-well potential bilinearly coupled to a bath of harmonic oscillators. Flux correlation functions and thermal rate constants have been calculated at two different temperatures for a range of coupling strengths. The results have been compared to the fully quantum simulations of Topaler and Makri [J. Chem. Phys. 101, 7500 (1994)] with the real path integral method.
最近提出的混合量子-经典方法被扩展到有限温度下的应用。该方法旨在处理由低维量子部分（主要系统）与经典描述的耗散浴耦合组成的复杂系统。该方法基于一种形式主义，展示了如何系统地修正近似零阶演化规则。这些修正定义在总量子哈密顿量中，并通过引入浴自由度的冻结高斯近似来取经典极限。主要系统的演化由修正的传播子控制，从而产生精确的量子动力学。该方法已在描述凝聚相环境中质子转移的标准模型系统上进行了测试：一个对称的双阱势线性耦合到一组谐振子浴。在不同的温度下，对于一系列耦合强度，计算了通量相关函数和热速率常数。将结果与 Topaler 和 Makri [J. Chem. Phys. 101, 7500 (1994)]的全量子模拟进行了比较，使用的是真实路径积分方法。
