LASER SPECTROSCOPY OF PHOTOLYTICALLY PRODUCED FREE RADICALS

Abstract

The production of free radicals in an expansion of the Campargue type is accomplished by excimer laser photolysis of a suitable precursor seeded into the inert carrier gas. Extensive, and controllable cooling of the free radicals occurs after photolysis through collisions with the carrier gas, and rotational temperatures of $<$10K can be achieved. The free radicals are characterized by fluorescence excitation spectroscopy. Results for a number of polyatomic free radicals will be described. For these species the rotational cooling leads to a great simplification of the spectra, and considerably assists the assignment of the observed transitions.