IMPROVED FEYNMAN PROPAGATORS ON A GRID AND NONADIABATIC CORRECTIONS WITHIN THE PATH INTEGRAL FRAMEWORK
IMPROVED FEYNMAN PROPAGATORS ON A GRID AND NONADIABATIC CORRECTIONS WITHIN THE PATH INTEGRAL FRAMEWORK
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DOI：
10.1016/0009-2614(92)85654-s
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发表时间：
1992-06-05
影响因子：
2.8
通讯作者：
MAKRI, N
中科院分区：
文献类型：
--
作者：
MAKRI, N
通过构造改进的Feynman传播子，将微扰论和基组计算中广泛采用的用好的表示作为问题的零阶描述的思想推广到量子力学的路径积分公式中.最佳零阶传播子一般不能用封闭形式表示，因此只能用数值方法构造并存储在一维网格上。在离散路径积分计算中使用改进的传播算子涉及到Monte Carlo技术的一个微不足道的修改，并导致更少的时间片收敛。应用准绝热传播子耦合到一个谐波浴系统导致低维路径积分与非局部影响功能，其中包括非绝热修正的玻恩-奥本海默近似和（与化学过程的典型参数），可以通过求积进行评估，提供了一个准确的方法，用于调查系统浴哈密顿量的真实的时间量子动力学。
The idea Of using a good representation as the zeroth order description of a problem, which is widely used in perturbation theory and in basis set calculations, is extended to the path integral formulation of quantum mechanics by constructing improved Feynman propagators. The best zeroth order propagators cannot be expressed in closed form in general, and are therefore constructed numerically and stored on one-dimensional grids. Use of improved propagators in discretized path integral calculations involves a trivial modification of Monte Carlo techniques and leads to convergence with fewer time slices. Application of a quasi-adiabatic propagator to a system coupled to a harmonic bath leads to a low-dimensional path integral with a non-local influence functional which incorporates the non-adiabatic corrections to the Born-Oppenheimer approximation and which (with parameters typical of chemical processes) can be evaluated by quadrature, providing an accurate method for investigating the real time quantum dynamics of system-bath Hamiltonians.