Molecular Collision Dynamics: State-Resolved Studies by "Half-Collision" Techniques

在化学系实验物理化学计划的这个项目中，爱荷华大学的P.Kleiber、K.Sando和W.Stwalley教授将继续他们的研究，利用状态选择性半碰撞技术研究氢分子与激发的金属原子反应的化学动力学，特别是能量转移碰撞。对碱性双原子分子的近阈值光解离动力学的研究也在继续。关于激发金属原子与分子之间反应的拟议实验将用于检验此类过程的理论模型。要显著偏离理论上预测的行为，将需要对模型进行修订，或者至少对其有效性范围进行限制。碱性双原子分子的光解离也存在理论模型。在这些模型中，解离通常被视为完全碰撞过程的“半碰撞”模拟，后者由两个进入的粒子和两个新出现的粒子组成。然而，这样的理论往往不能服从简单的物理解释，也不能轻易地应用于复杂的解离过程。在目前感兴趣的一些情况下，例如超冷原子之间的碰撞，基本的物理学还没有被很好地理解，以至于无法自信地应用任何理论方法。这项研究中所做的实验将提供有助于澄清碰撞和光解动力学领域中的许多问题的信息。

In this project in the Experimental Physical Chemistry Program of the Chemistry Division, Professors P. Kleiber, K. Sando, and W. Stwalley of the University of Iowa will continue their investigations of the chemical dynamics of the reaction of hydrogen molecules with excited metal atoms, especially energy transfer collisons by means of state-selective half-collision techniques. Also continued are studies of the near threshold photodissociation dynamics of alkali diatomic molecules. %%% The proposed experiments on reactions between excited metal atoms and molecules will serve to test theoretical models for such processes. Significant deviations from the theoretically predicted behavior will require a revision of a model or at least place limits on its range of validity. Theoretical models also exist for the photodissociation of alkali diatomic molecules. In these models a dissociation is often viewed as a "half-collision" analog of a full collision process, the latter consisting of two incoming and two emerging particles. Such theories are, however, often not amenable to simple physical interpretation and can not easily be applied to complex dissociation processes. In some cases of current interest, such as collisions between ultra-cold atoms, the underlying physics is not understood well enough to allow application of any of the theoretical methods with confidence. The experiments done in this research will provide information that will assist in the clarification of many questions in the domain of collision and photodissociation dynamics.