Theoretical and Experimental Study of Electronic Non- adiabaticity in Molecular Collisions and Photofragmentation

在本项目中，由物理化学计划的支持， 化学系，教授。M.大学的亚历山大 马里兰州大学的P. Dagdigian和约翰霍普金斯大学的P. Dagdigian将 进行理论和实验的联合努力，以确定 分子碰撞和光解离受到 分子能态 特别是，由于分子能量 国家很少是理想化的，独立的国家， 理论公式的初始阶段， 它们之间的关系在决定 碰撞和光解离过程。 几 原型自由基分子，包括二原子和三原子 单氢化物物种，将进行研究。 理论 该项目的一部分（M。亚历山大）涉及的发展 新的方法来阐明分子机制， 碰撞和光解离。 实验部分（P。 Dagdigian）涉及确定横截面 分子经历能量变化的非弹性碰撞。 还有待确定的是分布在内部 分子碎片的能量状态， 母体分子的光解离。 %%% 分子能量主要被认为是 平移，旋转，振动和电子 运动，后者由轨道和自旋组成 捐款. 将总能量分解为 然而，独立贡献只是理想化的第一 分子结构概念模型的一步， 动力学，并允许这些运动之间的相互作用， 是必要的，以解释观察到的分子 特性. 光解离和碰撞 分子也受到这些相互作用的影响， 在开壳（自由基）分子中尤其明显。 在这项研究中进行的调查将 有助于理解这些过程，并将 协助确定《公约》的有效期限， 开壳基本玻恩-奥本海默近似 分子。

In this project, supported by the Physical Chemistry Program of the Chemistry Division, Profs. M. Alexander of the University of Maryland and P. Dagdigian of Johns Hopkins University will pursue a joint theoretical-experimental effort to determine how molecular collisions and photodissociations are affected by molecular energy states. In particular, since molecular energy states are rarely the idealized, independent states used in the initial stages of theoretical formulations, the interactions between them play a signifant role in determining the details of the collision and photodissociation processes. Several prototypical free radical molecules, including di-and triatomic monohydride species, will be investigated. The theoretical portion of this project (M. Alexander) involves the development of new methods to elucidate the mechanism of molecular collisions and photodissociation. The experimental portion (P. Dagdigian) involves the determination of cross sections for inelastic collisions in which molecules undergo energy changes. Also to be determined are the distributions over the internal energy states of a molecular fragment that results from the photodissociation of the parent molecule. %%% Molecular energies are considered in the main to be the result of translational, rotational, vibrational and electronic motions, with the latter being made up of orbital and spin contributions. This separation of the total energy into independent contributions is, however, only an idealized first step in the conceptual model of molecular structure and dynamics, and allowing for interactions between these motions is necessary in order to account for the observed molecular properties. Photodissociations and collisions between molecules are also affected by these interactions, which are particularly evident in open shell (free radical) molecules. The investigations to be carried out in this research will contribute to the understanding of these processes and will assist in establishing the limits of validity of the fundamental Born-Oppenheimer approximation to open shell molecules.