Time-dependent Approach in Theoretical Chemistry

本项目的目的是在电子相关和电子-核相互作用问题中发展新的时变方法。建立定量处理时间相关事件的理论，以及适用于分子设计和化学反应设计的大系统方法，是一个迫切需要解决的问题。因此，我们的重点是发展新的理论和方法及其在化学现象中的应用：一种构建势能表面的方法，这对化学反应至关重要，准确而有效；基于势面上动态反应路径的反应路径模型波包法包括电子-核相互作用；以及这些方法在化学反应中的应用。提出了一种新的含电子相关的时变密度泛函方法和解析能量梯度方法，并与Handy教授合作编写了程序代码。建立了多维势面隧穿理论，并将其应用于多原子化学反应。与Carbo教授合作，提出了一种有效的大哈密顿矩阵对角化方法。数值实验验证了新算法的准确性和有效性。与Cederbaum教授讨论了包含电子-核相互作用的波包方法和基于动态反应路径构建势能面的方法。将上述方法应用于多原子分子解离机理和自由基荧光等化学现象的研究。

The purpose of the present project is developing new time-dependent approaches in the electronic correlation and electron-nuclear interaction problems. It is an urgent problem to develop theories which can treat the time-dependent events quantitatively, as well as methods for large-scale systems which are applicable to the molecular design and chemical reaction design. Our focus was, therefore, on the development of new theories and methods and their applications to chemical phenomena : a method for constructing potential energy surfaces, which is crucial for chemical reaction, accurately and efficiently ; a reaction path model based on dynamic reaction path on the potential surfaces ; wave packet method including electron-nuclear interaction ; and the application of these methods to the chemical reactions.A new time-dependent density functional method and an analytic energy gradient method including electron correlation were formulated, and their program code were developed by collaborating Professor Handy. A theory for tunneling in multidimensional potential surfaces was also formulated and applied to polyatomic chemical reactions. An efficient diagonalization method of large Hamiltonian matrices was developed by collaborating Professor Carbo. Numerical tests were performed to verify the accuracy and efficiency of the new algorithm. A wave packet method including electron-nuclear interaction and a method for constructing potential energy surfaces based on the dynamic reaction path were discussed with Professor Cederbaum. The methods mentioned above were applied to the studies of several chemical phenomena such as dissociation mechanisms of polyatomic molecules and fluorescence of radicals.