Professor Miller is supported by the Experimental Physical Chemistry Program to investigate the spectroscopy of various transient chemical species. Such chemical intermediates as reactive atoms, free radicals, and molecular ions often play critical roles in reactions in combustion, solvation, synthetic processes, and the chemistry of the atmosphere. Spectroscopic identification and characterization is important both for monitoring these intermediates and for understanding their structures and interactions. Two facilities constructed under prior NSF support are used in this work. One facility, dedicated to the study of ionic clusters, uses laser-induced fluorescence to probe cluster structure and time-of-flight mass spectrometry to determine the number of atoms. The second apparatus prepares neutral radicals in a pulsed supersonic jet for ultra-high resolution pulsed laser spectroscopy designed to reveal details of rotational structure. Species under investigation range from small polyatomics to multi-ring aromatic radicals and include clusters containing ions or open-shell radicals.
