Inelastic Electron Collisions with Molecules and Clusters

低能电子在许多基础和应用领域发挥着至关重要的作用。它们可以引发与介电老化、表面工程、辐射损伤、癌症治疗和大气物理相关的特定化学反应。一个特别重要的过程是解离电子附着(DEA)，涉及电子被分子捕获，随后分子键断裂。尽管对这一过程进行了几十年的实验和理论研究，但对它的理解还远远不完整。这与涉及分子簇的DEA过程特别相关，分子簇是许多分子被弱力松散地结合在一起。本项目计划从理论上研究气相和团簇环境中的电子-分子碰撞过程。所提出的活动将推进电子与分子和团簇相互作用的理论，以及团簇环境中的分子相互作用。这项研究将在碰撞物理与化学控制、放射生物学和大气科学相结合的领域创造新的知识。这项研究将涉及跨学科的努力以及与其他领域的科学家的合作。它将在更广泛的领域培训学生，包括几个子学科。教学中将结合低能电子在化学、生物和环境科学的不同领域中的作用的例子。该项目的主要重点是多原子分子的DEA的非局域复势理论的发展。这一理论将允许将长程相互作用效应适当地纳入多原子分子的DEA描述中，这是以前所没有的。这些效应可能会在DEA中引起特殊类型的共振，即振动费什巴赫共振。它们以前是在一个反应坐标的近似下描述的，该项目包括将该理论推广到几个振动自由度的情况的计划。此外，还将利用多重散射理论研究团簇环境对DEA过程的影响。目前几乎没有关于这些效应的实验或理论信息，尽管它们对于理解辐射对生物相关分子的损害机制很重要。

Low-energy electrons play a critical role in a large number of fundamental and applied fields. They can induce specific chemical reactions which are relevant to dielectric aging, surface engineering, radiation damage, cancer therapy, and atmospheric physics. A particularly important process is dissociative electron attachment (DEA) involving electron capture by a molecule with the following break-up of a molecular bond. In spite of decades of experimental and theoretical studies of this process the understanding of it is far from complete. This is especially relevant to DEA processes involving molecular clusters, which are many molecules loosely bound by weak forces. The present project plans to theoretically study electron-molecule collision processes in gas phase and in cluster environments. The proposed activities will advance the theory of electron interaction with molecules and clusters, and molecules in a cluster environment. This research will create new knowledge in the areas connecting collision physics with chemical control, radiobiology and atmospheric science. The research will involve interdisciplinary efforts and collaborations with scientists from other fields. It will train students in broader areas including several subdisciplines. Examples demonstrating the role of low-energy electrons in different areas of chemistry, biology and environmental science will be incorporated in teaching.The project's major focus is on the development of the nonlocal complex potential theory of DEA for polyatomic molecules. This theory would allow a proper incorporation of long-range interaction effects into the DEA description for polyatomic molecules which has previously been absent. These effects might cause special type of resonances, vibrational Feshbach resonances, in DEA. They were previously described in the approximation of one reaction coordinate, and the project includes plans to generalize the theory to the case of several vibrational degrees of freedom. In addition, the effects of the cluster environment on the DEA processes will be investigated by the use of multiple-scattering theory. Almost no information on these effects, experimental or theoretical, is presently available, although they are important for the understanding of the mechanism of radiation damage to biologically-relevant molecules.