Subpicosecond uv kinetic spectroscopy: Photolysis of thallium halide vapors

The formation of Tl atoms resulting from subpicosecond UV (308, 248.5 nm) photolysis of TlCl and TlI vapors is probed via subpicosecond UV kinetic absorption spectroscopy. Unusual line shapes are observed for a period lasting roughly 1 ps, from the moment the atomic transition first appears, to the point at which the final, asymptotic, line shape is attained. These spectra are explained in terms of a model based upon the transient behavior of the polarization induced by the probe continuum pulse as it interacts with a growing population of two-level atoms whose resonance frequencies shift in time. © 1988.