Electronic Structure theories for Chemical Reactions

我们用分子的电子结构方法对化学反应进行了理论研究。本项目的主要内容是(1)电子激发态的化学反应，(2)包括重原子和过渡金属原子在内的体系的反应，以及(3)发展定量解释化学反应的新的轨道相互作用理论。对于第一个主题，我们发展了一种计算不同电子态之间的非绝热耦合元素的方法，并将其应用于估算第一激发态甲醛的内转换速率常数。该方法得到的速率常数与已有的实验结果吻合较好。这项工作被认为是多原子分子内转化率的首次非经验计算。在第二个主题中，我们建立了一种强有力的方法来设计新的化合物并利用从包括重元素的体系的从头计算中获得的信息来控制反应活性。在过渡金属催化作用下，进一步计算了烯烃聚合反应的势能面，获得了揭示催化反应机理的重要信息。最后，基于轨道相互作用理论，提出了一种新的化学硬度的解释。

We have carried out theoretical studies of chemical reactions using electronic structure methods for molecules. The main subjects of the present project were (1) chemical reactions in the electronically excited states, (2) reactions of the systems including heavier and transition metal atoms, and (3) to develop new orbital interaction theories interpreting chemical reactivities in a quantitative manner. For the first subject, we developed a method for calculating the nonadiabatic coupling elements between different electronic states and applied it in estimating the internal conversion rate constants of the first excited state formaldehyde. This method provided the rate constants which are in good agreement with the available experimental findings. This work is regarded as the first nonempirical calculations of the internal conversion rate of polyatomic molecules. In the second subject, we established a powerful method to design new compounds and control the reactivities using the information obtained from ab inition calculations of systems including heavy elements. We further calculated the potential energy surfaces of the polymerization reactions of olefines with the aid of transition metal catalysis and obtained important informations to reveal the mechanism of catalytic reactions. Finally, we proposed a new interpretation of chemical hardness based on the orbital interaction theories.