Spectroscopy and Dynamics of Open-Shell van der Waals Molecules

点击翻译按钮获取中文摘要

In this project in the Physical Chemistry Program of the Chemistry Division, Prof. M. Heaven of the Chemistry Department of Emory University will study the weak bonding interactions and predissociation dynamics of open shell van der Waals molecules. Specifically, the van der Waals complexes formed by the hydroxyl, cyanogen and methyne radicals with rare gas atoms will be investigated. The excited electronic states will be characterized by high resolution fluorescence excitation spectroscopy, fluorescence depletion spectroscopy, and quantum beat measurements. The electronic ground states will be probed by stimulated emission pumping techniques. For the lighter systems, ab initio calculations of the potential energy surfaces will be performed to complement the experimental results. Electronic and vibrational predissociation will be investigated through wavelength resolved fluorescence and pulsed laser pump-probe measurements. The study of weakly bound van der Waals complexes is one of the frontier areas of contemporary physical chemistry. While numerous van der Waals complexes formed by stable (closed shell) molecules have been investigated, the study of such complexes in which one of the component members is a radical (molecular fragment) is still in its early stages. Owing to the presence of significant electron spin couplings of the radical with its closed shell partner, theoretical models developed for the bonding interactions in closed shell van der Waals complexes are not applicable to open shell systems. This research provides an important data base for open shell van der Waals complexes for the development of theoretical models of these systems. The results of this research are of direct relevance to work on collisional processes involving open shell diatomics which is currently pursued in several laboratories.