Inelastic Electron Collisions with Molecules and Clusters

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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.