Spin-orbit coupled diabatic potential energy surfaces for quantum dynamics

电子态之间的振动和相对论耦合是分子动力学中非绝热效应的根源，通常对反应和光谱有重要影响。重要的例子是有机光化学中的超快无辐射过程，它是由锥形交叉诱导的，或者是与过渡金属的催化反应，涉及自旋禁忌机制。对这种非绝热过程的基本认识和理论处理需要正确地处理这种耦合和确定完全耦合的势能面。该项目的目标是建立一种方法来产生包括中型分子的相对论(例如自旋-轨道)耦合在内的全维非绝热PESS，并将这一新方法应用于重要的基准系统。这种方法将高精度地处理所有相关的耦合效应，并将产生封闭的数学形式的PESS，用于量子动力学研究。为此，将使用我们在过去几年中发展起来的被称为有效相对论表示耦合(ERCAR)的方法。到目前为止，该方法已应用于甲基碘(CH3I)体系，该体系在甲基碎片中具有特别简单的电子结构。接下来，我们想将ERCAR方法应用于碘苯(C6H5I)，它在苯碎片中具有更具挑战性的电子结构，可能会在量子动力学中产生新的效应。拟议项目的目标是彻底从理论上处理碘苯的光解离动力学，并与实验和甲基碘的光解动力学进行比较。

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.