Molecular Structure and Dynamics Beyond the Born-Oppenheimer Approximation

普渡大学的爱德华·格兰特在实验物理化学计划的支持下，继续他在小分子高激发态的态对态光电离和分子内弛豫动力学的研究。这项工作的主要目标是为一些多原子系统积累足够分辨率的详细状态光谱信息，以支持全面的多通道量子亏损理论计算。要研究的体系包括形成闭壳阳离子的碳氢化合物和金属中心自由基。PI将使用多共振激发技术对共振线型和与跃迁相关的能量进行高分辨率光谱测量，这些跃迁与电离和解离连续谱相耦合，并使用专门的检测方法进行光选择，以研究阳离子和前体自由基的电子基态的振动结构。描述孤立分子中能量流动的努力大大增加了我们对化学反应的理解，多年来一直是化学物理研究的一个重要焦点。分子内弛豫的研究至今仍是实验分子动力学和理论分子动力学之间的一个重要的接触点。尤其重要的是电子自由度和核间自由度之间的能量转移。这类过程的详细动态可能会引起重大的化学后果。例如，与电子坐标和核间坐标之间的能量转移动力学有关的问题是指导化学变化结果的当代努力的基础。

Edward Grant of Purdue University is supported by the Experimental Physical Chemistry Program to continue his research on state-to-state photoionization and dynamics of intramolecular relaxation in highly excited states of small molecules. The main objective of this work is to accumulate, for a number of polyatomic systems, state-detailed spectroscopic information of sufficient resolution to support full-scale Multichannel Quantum Defect Theory calculations. Systems to be studied include hydrocarbon and metal-centered free radicals that form closed-shell cations. The PI will use multiresonant excitation techniques to make high-resolution spectroscopic measurements of resonant lineshapes and energies associated with transitions to states which are coupled to ionization and dissociation continua, and photoselection with specialized detection methods to study rovibrational structure in the electronic ground states of cations and precursor free radicals. The effort to describe energy flow in isolated molecules has added considerably to our understanding of chemical reactivity, and served for many years as an important focus of research in chemical physics. The study of intramolecular relaxation remains today a vital point of contact between experimental and theoretical molecular dynamics. Particularly important is the transfer of energy between electronic and internuclear degrees of freedom. The detailed dynamics of such processes can give rise to significant chemical consequences. For example, issues associated with the dynamics of energy transfer between electronic coordinates and internuclear ones underlie contemporary efforts to direct the outcomes of chemical transformations.