多原子体系非绝热动力学的近似理论方法

摘要

Nonadiabatic dynamics is ubiquitous in photo-physical and photo-chemical processes.The description of nonadiabatic transitions requires the treatment of coupled electron-nuclei motions.Exact quantum dynamical calculations,due to the insurmountable computational scaling with the size of the system,are only applicable to small molecular systems.In recent years,several approximat methods based on the quantum-classical dynamics were proposed to describe the nonadiabatic dynamics of polyatomic molecular systems.This article provides a concise review of different versions of quantum-classical dynamics approaches including the classical Ehrenfest method,the surface-hopping technique,and the mixed-quantum-classical dynamics in terms of the Winger representation.The pros and cons of the on-the-fly numerical implementation of these schemes combining the ab initio electronic structure calculations are discussed and perspectives on further development of quantum-classical treatment of nonadiabatic dynamics are given.%非绝热动力学普遍存在于光物理和光化学过程中。描述非绝热跃迁需要处理电子-原子核间的相互耦合运动。由于计算量随体系尺度增大剧烈增长,准确的量子动力学计算目前只适用于描述小分子体系。为了研究多原子分子体系的非绝热过程,近年来发展了一些基于量子-经典动力学近似方法。本文将对典型的这类方法包括经典Ehrenfest方法、面跳跃方法、基于Wigner表示的混合量子-经典方法进行简要的介绍,并讨论如何将量子-经典动力学方法与电子结构从头算手段相结合,模拟非绝热过程。重点阐明各种方法的基本思想和优缺点,并对该领域的发展进行展望。