Spectroscopy and Dynamics of Gas Phase Organometallic Species

点击翻译按钮获取中文摘要

Jim Weisshaar of the University of Wisconsin in Madison is supported by the Experimental Physical Chemistry Program to continue his reactivity studies involving gas phase reactions of bare transition metal atoms (neutral or ionic) with small alkanes or alkenes, under controlled conditions of initial electronic state and collision energy. Rate constants and branching ratios will be measured as a function of temperature. In the case of the metal ion, crossed beams will be exploited to determine the time scale of reaction with 200 ns resolution Ultimately, these measurements will be extended to reactions of ligated metal atoms (MO, MCH3, MCO) and small metal cluster cations. Finally, laser spectroscopy will be used to determine bond dissociation energies, geometry, and the electronic and vibrational structure of simple organometallic radicals such as MCH2, MCH3, and their cations. Saturated hydrocarbon molecules such as methane and ethane are abundant sources of carbon, but they are relatively inert. Their chemical reactivities can be significantly enhanced, however, by catalysts of transition metal atoms. The physical chemistry of this activation process is not well understood and this research is devoted to improving our knowledge of the interactions between metal atoms and hydrocarbon molecules. Results of this research will affect our understanding of solution-phase organo-metallic chemistry, heterogeneous catalysis and surface chemistry. Furthermore, the data obtained in these investigations will be of use in the development of theoretical models and techniques for the calculation of interaction potentials between metals and hydrocarbon molecules.