Spin-orbit coupled diabatic potential energy surfaces for quantum dynamics

电子态之间的振动耦合和相对论耦合是分子动力学中非绝热效应的起源，并且经常对反应和光谱产生重大影响。重要的例子是有机光化学中的超快无辐射过程，这是由锥形交叉引起的，或者是与过渡金属的催化反应，涉及自旋禁止机制。对这种非绝热过程的基本理解和理论处理需要正确处理这种耦合和确定完全耦合的势能面（PES）。该项目的目的是建立一种方法来产生全维非绝热PES，包括相对论（e。G.自旋-轨道）耦合，并将这种新方法应用于重要的基准系统。该方法将以高精度处理所有相关的耦合效应，并将以封闭的数学形式产生可用于量子动力学研究的PES。为此，我们的方法称为有效的相对论耦合渐近表示（ERCAR），这已经在过去几年中开发的，将被使用。到目前为止，该方法已被应用到甲基碘（CH 3 I）系统，其中有一个特别简单的电子结构内的甲基片段。接下来，我们想将ERCAR方法应用于碘苯（C6 H5 I），它在苯片段中具有更具挑战性的电子结构，可能会导致量子动力学的新效应。该项目的目标是通过与实验和碘甲烷的比较，对碘苯的光解离动力学进行彻底的理论处理。

Vibronic and relativistic couplings among electronic states are the origin of nonadiabatic effects in molecular dynamics and often have a significant impact on reactions and spectra. Important examples are ultrafast radiationless processes in organic photochemistry, which are induced by conical intersections, or catalytic reactions with transition metals involving spin-forbidden mechanisms. The fundamental understanding and theoretical treatment of such nonadiabatic processes requires the correct handling of such couplings and the determination of fully coupled potential energy surfaces (PESs). The aim of the proposed project is the establishment of a method to generate full-dimensional diabatic PESs including relativistic (e. g. spin-orbit) couplings for medium sized molecules and to apply this new methodology to important benchmark systems. The method will treatall relevant coupling effects with high accuracy and will yield PESs in closed mathematical form to be used in quantum dynamics studies. To this end, our method called Effective Relativistic Coupling by symptotic Representation (ERCAR), which has been developed over the past few years, will be used. So far the method has been applied to the methyl iodide (CH 3 I) system, which has a particularly simple electronic structure within the methyl fragment. Next we want to apply the ERCAR methodology to iodobenzene (C6H5I) which has a more challenging electronic structure in the benzene fragment, presumably leading to new effects in the quantum dynamics. The goal of the proposed project is a thorough theoretical treatment of the photodissociationdynamics of iodobenzene in comparison to experiment and that of methyl iodide.