Inelastic Electron Collisions with Molecules and Clusters

低能电子在许多基础和应用领域中起着至关重要的作用。它们可以诱导与介质老化、表面工程、辐射损伤、癌症治疗和大气物理有关的特定化学反应。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够。这与涉及分子簇的DEA过程特别相关，分子簇是由弱力松散结合的许多分子。本项目拟从理论上研究气相和团簇环境下的电子-分子碰撞过程。所提出的活动将推进电子与分子和团簇以及分子在团簇环境中的相互作用理论。这项研究将在碰撞物理学、化学控制、放射生物学和大气科学等领域创造新的知识。这项研究将涉及跨学科的努力，并与其他领域的科学家合作。它将在更广泛的领域培养学生，包括几个分支学科。低能电子在化学、生物和环境科学等不同领域的作用将被纳入教学。本项目主要研究多原子分子DEA的非局部复势理论。这一理论将允许在DEA描述中适当地纳入以前不存在的多原子分子的远程相互作用效应。这些效应可能导致DEA中特殊类型的共振，即振动费什巴赫共振。它们以前是在一个反应坐标的近似中描述的，该项目包括将理论推广到几个振动自由度的情况的计划。此外，利用多重散射理论研究了簇环境对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伤机制很重要。

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.