Theoretical Studies of Spin-Forbidden and Electronically Nonadiabatic Processes

在化学系理论与计算项目的资助下，Yarkony教授将研究禁止自旋和电子非绝热化学中的几个问题。这些过程在决定许多工业上重要的化学反应的速率方面起着重要作用。Yarkony教授将开发计算机算法，包括：(1)在Breit-Pauli近似下，利用基于准等微扰理论的大尺度组态函数展开确定相对论性波函数的能力；(2)利用解析梯度方法定位显著电子非绝热区域，即允许；避免和实际交叉的势能面，并确定在这些区域的导数耦合。他将考虑非绝热的电子猝灭反应，如Na+HCl之间的电子猝灭反应，这是最近实验和理论研究的对象。他将关注绝热-绝热状态转换的本质。其他需要调查的领域包括：(1)光化学解离过程；(2)He-H2体系的全局势能面和导数耦合的表征；(3)化学激光能量转移中作为储能中间体的候选分子NO+和O2+以及SiCl2、SiH2、SiH2、SiH2和SiH2的自旋禁止偶极子允许辐射衰变过程的研究。和SiHCl，它们通过气相沉积在半导体制造中起作用。

With this grant in the Theoretical and Computational Program of the Chemistry Division Professor Yarkony will investigate several problems in spin-forbidden and electronically nonadiabatic chemistry. These processes play a major role in determining the rate of a number of industrially important chemical reactions. Professor Yarkony will develop computer algorithms which will include: (1) the capability for determining relativistic wavefunctions using large scale configuration state function expansions based on quasidegenerate perturbation theory within the Breit-Pauli approximation, and (2) the use of analytical gradient methods for locating regions of significant electronic nonadiabaticity, that is, allowed, avoided and actual crossings of potential energy surfaces, and for determining derivative couplings in these regions. He will consider nonadiabatic electronic quenching reactions such as that between Na+HCl which has been the object of recent experimental and theoretical studies. He will focus on the nature of the adiabatic-diabatic state transformations. Other areas to be investigated include: (1) photochemical dissociation processes, (2) a characterization of the global potential energy surfaces and derivative couplings for the He-H2 system, and (3) a study of spin-forbidden dipole-allowed radiative decay processes in the molecules NO+ and O2+, which are candidates for energy storage intermediates in energy transfer in chemical lasers, as well as the molecules SiCl2, SiH2, and SiHCl which play a role in semiconductor fabrication through vapor deposition.