An Excimer Laser System will be purchased and used to support several established research programs in combustion chemistry, materials processing , and chemical analysis at George Washington University. These programs include laser-solid interaction in synthetic diamond film formation, laser sampling of glass and ceramic targets for chemical analysis, laser production of radical species important in combustion processes, and photodissociation of chlorinated hydrocarbons. In the first two areas, the goal will be to follow changes occurring on the surface and within the bulk of the targets and to examine the properties of the generated plumes. Methods of investigation will include time-of-flight mass spectrometry, kinetic energy measurement of the ions produced, and analysis of particulates in the plumes. In addition, laser-solid interactions will be examined theoretically for a broad range of lasers and selected materials. In the third area, excimer laser photolysis will be used to prepare radical species which are important in combustion systems. Absorption spectra for these species will then be obtained using an existing tunable diode laser spectrometer. Use of excimer laser photolysis followed by IR absorption as a diagnostic for chlorinated hydrocarbons in lab scale diffusion flames will also be explored. The general objectives of the first two activities are to enhance the understanding of laser-solid interactions and to use this knowledge in preparative and analytical applications. This will include optimization of laser sampling and pulsed laser deposition processes. In addition, a better understanding of synthetic diamond formation is a goal. In the latter activities, excimer laser photolysis has become the technique of choice for the preparation of a number of gas phase radical species for fundamental spectroscopic studies. Additionally, it is proposed that excimer laser photolysis of chlorinated hydrocarbons might also be used for the detection of undesirable combustion products.
