Theoretical Aspects of Chemical Dynamics: Ion-Molecule Collisions, Energy-Time Analysis of Molecular Spectra, and Assignment of Quantum States

康奈尔大学的埃兹拉教授得到了 理论和计算化学计划，继续他的工作， 化学动力学的理论研究。 特别是 该项目是一项计算研究， 态的研究通过量子，经典和半经典的方法。 在下一个赠款期间，他将调查 离子分子碰撞，特别强调的形成和 长寿命碰撞复合物的衰变。 这项研究还将重点 半经典周期轨道理论的发展， 分子振动光谱的解释， 足够高的能量，他们超越了传统的制度， 光谱技术 这些主题涉及几个基本问题 化学和分子物理学中的问题，即能量的命运 长寿命分子复合物的分布和统计与 瞬态物质单分子衰变的非统计行为。 在接下来的两年里，以斯拉教授将关注 分子内部运动的理论分析，因为它们 振动，旋转，互相碰撞。研究这些 原子核运动的模式有助于我们更深入地了解 决定了分子的反应倾向， 给定条件。 该研究小组将研究一些 与这一总主题相关的主题。 首先，他们将调查 电荷之间可能发生的“粘性”碰撞的性质 例如，在大气化学反应中， 重要性 这种粘性碰撞对于后续的 发生化学反应。 另一个主要议题是 使分子内核运动的性质能够被 从分子振动光谱中直接推断出来。 多 这项工作利用了半经典的想法：也就是说，理论， 正确的相对于量子力学，同时保留直观的 吸引力的经典球和弹簧图片的核运动。 定期 原子核的经典运动，那些不断重复的运动， 无穷大，被发现在理解 光谱和核动力学之间的联系。

Professor Ezra of Cornell University is being supported by the Theoretical and Computational Chemistry program to continue his work on the theoretical investigation of chemical dynamics. Specifically the project is a computational study whereby complex high lying vibrational states are investigated by quantum, classical and semiclassical methods. During this next grant period he will investigate the dynamics of ion-molecule collisions, with particular emphasis on the formation and decay of long lived collision complexes. This research will also focus on the development of semiclassical periodic orbit theory as an aid in the interpretation of molecular vibrational spectra which are of sufficiently high energy that they lie beyond the regime of traditional spectroscopic techniques. These topic address several fundamental problems in chemical and molecular physics namely the fate of energy distribution of long lived molecular complexes and statistical versus non-statistical behavior in the unimolecular decay of transient species. During the following two years Prof. Ezra will be concerned with the theoretical analysis of the internal motions in molecules, as they vibrate, rotate, and collide with one another. The study of these patterns of nuclear motion leads to a deeper understanding of the factors that determine the propensity of molecules to undergo reaction under given conditions. This research group will be studying a number of topics relevant to this general theme. First, they will investigate the nature of the ``sticky'' collisions that can occur between charged species and uncharged molecules in, for example, reactions of atmospheric importance. Such sticky collisions are often essential for subsequent chemical reaction to occur. Another major topic is the development of methods that enable the nature of nuclear motions within molecules to be inferred in a fairly direct way from molecular vibrational spectra. Much of this work exploits semiclassical ideas: that is, theories that are correct with respect to quantum mechanics, while retaining the intuitive appeal of classical ball-and-spring pictures of nuclear motion. Periodic classical motions of nuclei, those that repeat over and over ad infinitum, are found to play an important role in understanding the connection between spectra and nuclear dynamics.