In this project in the Experimental Physical Chemistry Program of the Chemistry Division, Kevin Lehmann of Princeton University will develop two spectroscopic tools to aid in studying intramolecular vibrational energy redistribution (IVR) in small polyatomic molecules. The first technique is an optical-optical double resonance method which allows very highly vibrationally excited levels of the ground state to be populated in order to study the effect of the large anharmonicity on the vibrational motion. The other technique is a time-resolved, infrared-pump/Raman probe method for exploring the final IVR distributions after vibrational excitation of hydrogen atom stretches. Finally, Lehmann will develop theoretical tools to interpret the newly acquired spectra. %%% An understanding of the effects of large amounts of vibrational excitation in a molecule directly impacts our understanding of the fundamental processes by which many types of reactions occur. In this research Lehmann will study the effects of vibrational energy on the motions of bonds in a molecule as well as the elucidation of the pathways by which this excess energy is dissipated. This information has impact on the basic understanding of many reactive processes, from atmospheric chemistry to combustion to synthesis using plasmas.
