水分子高激发态全维电子结构及光解离动力学的理论研究

Water widely distributes on earth and among the universe, and its photodissociation dynamics play a key role in atmosphere chemistry and astronomy. In recent years, many experimental researches were performed based on advanced spectroscopy techniques such as free electron laser and the third generation synchrotron radiation, and many theoretical works have been carried out to explain the experimental observations. However, most theoretical studies can only deal with the non-adiabatic dynamics among the ground and low excited states (X, A and B) for lacking the corresponding structure computations. This project will realize the high-dimensional structure computation for the high-excited states for multiatomic molecules by developing a new method combining multi-configuration self-consistent field (MCSCF) method and Table-CI algorithm. We select water to calculate its full-dimensional potential energy surfaces and study the photodissociation dynamics for the high-excited states with semi-classical dynamical method, and try to reveal the hidden physics.

水是地球和宇宙中含量丰富的分子,其光解离动力学对大气化学和天文学领域有重要价值。近年来，基于先进的自由电子激光、第三代同步辐射等谱学实验技术，开展了大量的实验研究，带动了相关的理论探索。然而受制于结构计算能力，目前的理论工作只能涵盖基态和较低激发态（X、A、B）的非绝热动力学。本项目拟结合Table-CI算法、多组态自洽场（MCSCF）方法以及部分经验性的参考组态选择机制，达到降低计算量、提高计算精度并避免大小一致性问题，进而实现多原子分子高维度高激发态的结构计算。具体将以水分子为研究对象，计算其高激发态的全维势能面，并结合动力学演化方法，研究水分子高激发态的光解离动力学，发掘其背后的物理机理。

水分子的光解离动力学对大气化学和天文学领域有重要价值。在理论研究方面受制于结构计算能力，目前的理论工作只能涵盖基态和较低激发态（X、A、B）的非绝热动力学。本项采用了结合Table-CI算法、多组态自洽场（MCSCF）方法以及部分经验性的参考组态选择机制，达到降低计算量、提高计算精度并避免大小一致性问题，实现了多原子分子高维度高激发态的结构计算。获得了高激发态的全维势能面，并结合动力学演化方法，研究水分子高激发态的光解离动力学，发掘了若干特殊的反应通道并计算了通道的分支比。同时我们将本项目的方法扩展用于研究水分子和高能电子的散射动力学问题，证实了高阶Born效应的重大影响。