The Development of Semiclassical Methods for the Evaluation of Vibrational Energy Relaxation Rates in Condensed Media

杜兰大学的迈克尔赫尔曼得到了 理论和计算化学计划，继续他的 理论工作的发展半经典方法的 压缩介质中振动弛豫率的估算。 目标 这项工作的重点是开发经过良好测试的准确方法， 足够灵活，以便能够评估 振动能弛豫在广泛的物理系统。 的 这些方法的发展战略采用了量子 分子振动运动的力学描述。 半经典技术被用来描述的时间演变， 系统中的非振动自由度。 这些方法允许 对于耦合的非振动程度的演变， 自由的量子振动跃迁，同时保留了大部分的 经典力学描述的计算优势。 分子获得和失去振动能的速率影响 反应动力学，能量传递，光谱解释 实验和许多其他过程中发生的液体，稠密气体 和固体。 这个问题的理论描述，在某种程度上 导致定量预测，要求振动 用量子力学处理。 之间的转换率的评估 在凝聚相系统中分子的量子态是一个 重要而具有挑战性的理论问题，需要耦合 量子技术与程序的平均超过众多的 冷凝相系统可用的配置。

Michael Herman, Tulane University, is supported by a grant from the Theoretical and Computational Chemistry Program to continue his theoretical work on the development of semiclassical methods for the evaluation of vibrational relaxation rates in condensed media. The goal of this work is the development of well tested, accurate methods that are sufficiently flexible so as to allow for the evaluation of the vibrational energy relaxation in a broad range of physical systems. The strategies for the development of these methods employ a quantum mechanical description of the vibrational motion of the molecules. Semiclassical techniques are employed to describe the time evolution of the nonvibrational degrees of freedom in the system. These methods allow for the coupling of the evolution of the nonvibrational degrees of freedom to the quantum vibrational transitions, while retaining much of the computational advantage of a classical mechanical description. The rate at which molecules gain and lose vibrational energy influences reaction kinetics, energy transport, the interpretation of spectroscopic experiments and many other processes occurring in liquids, dense gases and solids. The theoretical description of this problem, in a manner that leads to quantitative predictions, requires that the vibrations be treated quantum mechanically. The evaluation of transition rates between quantum states of the molecule in a condensed phase system is an important and challenging theoretical problem, requiring the coupling of quantum techniques with procedures for averaging over the multitude of configurations available to the condensed phase system.