Dr. Peter Felker is supported by a grant from The Experimental Physical Chemistry Program to perform structural studies on large van der Waals complexes using newly developed picosecond laser spectroscopic techniques. These new techniques which are referred to as rotational coherence spectroscopy (RCS) and Fourier transform stimulated emission pumping spectroscopy (FT-SEPS) provide important information about the structure and ground state potential energy surfaces for this very interesting class of molecules. RCS is a picosecond time-domain method based on the rotational quantum beat phenomenon, and it will be used to measure excited state rotational constants of large van der Waals complexes, hydrogen-bonded complexes, and species with torsional degrees of freedom. The goal of these experiments is to obtain information pertaining to the geometries of important species that are difficult to study with other high resolution techniques. FT-SEPS, an interferometric version of stimulated emission pumping spectroscopy, will be applied to high resolution studies of the ground-state rovibrational level structures of similar species. Here, again, the elucidation of geometries via the determination of (ground-state) rotational constants is the primary goal of the experiment. A secondary goal is to obtain information about inter- and intra-molecular potential energy srufaces via high resolution vibrational spectroscopy.
