High-Resolution Imaging of Photodissociation Dynamics in Ions and Neutral Molecules

韦恩州立大学的Arthur Suits和Oleg Vasyutinskii得到实验物理化学计划的支持，对离子和中性分子体系中的光化学过程进行高分辨率离子成像研究。其目的是了解多原子系统中的多表面动力学和非绝热过程；检查光解离中的相干效应；探索基态和激发态势能面的特征；揭示不寻常的反应机制；获得多通道过程的准确分支分数并探索控制这种分支的动力学问题；以及为这些具有挑战性的问题确定电子结构和动力学计算的基准。这些研究将利用最近开发的反射多质量成像设备来研究构象和振动介导的离子解离，这是一个新的方向，有望深入了解多原子系统的光驱动动力学。在离子光解研究的同时，多原子系统中的原子轨道极化将被用来研究原子和分子相互作用的独特细节。对完整角动量极化的详细研究，包括高阶矩的贡献，将被用来解开几个激发电子态起作用的情况下的衰变动力学。同时，将发展这些现象的新的理论描述，以便在实验和多原子光解过程的完整的量子描述之间建立直接的联系。这项研究的结果预计将导致对化学反应如何在最高细节上发生的重大见解，并可能迫使如何描述统计分子解离的方式发生实质性变化。这个项目将为不同的学生和博士后群体提供具有挑战性的研究机会。此外，由此产生的技术和软件进步将与众多研究小组自由分享。

Arthur Suits and Oleg Vasyutinskii of Wayne State University are supported by the Experimental Physical Chemistry Program to carry out high-resolution ion imaging studies of photochemical processes in both ionic and neutral molecular systems. The objectives are to understand multi-surface dynamics and nonadiabatic processes in polyatomic systems; to examine coherent effects in photodissociation; to explore features of the ground and excited-state potential energy surfaces; to reveal unusual reaction mechanisms; to obtain accurate branching fractions for multi-channel processes and explore the dynamical issues controlling this branching; and to benchmark electronic structure and dynamical calculations for these challenging problems. These studies will exploit the recently developed reflectron multimass imaging apparatus to study conformationally- and vibrationally-mediated dissociation of ions, a new direction that promises insights into the light-driven dynamics of polyatomic systems. In parallel with the ion photodissociation studies, atomic orbital polarization in polyatomic systems will be used to investigate atomic and molecular interactions in unique detail. Detailed investigations of the complete angular momentum polarization, including contributions from higher moments, will be used to unravel the decay dynamics in cases were several excited electronic states play a role. Concurrently, new theoretical descriptions of these phenomena will be developed so that a direct connection can be made between the experiment and a complete quantum description of the polyatomic photodissociation process. Outcomes from this research are anticipated to lead to major insights into how chemical reactions occur at the highest detail, and may compel substantial changes in how presumably statistical molecular dissociations are described. This project will provide challenging research opportunities for a diverse group of students and postdocs. As well, the technological and software advances that result will be shared freely with numerous research groups.