IR Transition Moments and Collisional Dynamics of Vibrationally Excited OH Radicals via Time-Resolved Laser Absorption Spectroscopy.

摘要

A high resolution, IR laser flash kinetic spectrometer has been constructed for time-resolved study of reactive kinetics, energy transfer, and radiative properties of atmospheric OH radicals. Theoretical efforts predict a dramatic J dependence to OH vibrational radiative rates, which are exploited experimentally in the flash kinetic spectrometer to infer an empirical dipole moment function. The accuracy of this dipole moment function is extended to include the turning points of up to OH(v=9) by use of rotationally resolved emission from FTIR studies of the H + O3 chemiluminescent reaction. The explicit knowledge of the state-to-state radiative rates permits an absolute measurement of the quantum yields for 193 and 248 nm photolysis production of OH from HNO3 and H2O2. Reaction rates of OH with atmospheric hydrocarbons are investigated, as well as the relaxation processes of highly rotationally excited OH formed by excimer laser photolysis of HNO3. This information bears directly on the characterization of highly vibrationally and rotationally excited OH 'airglow' emission from the stratosphere. Keywords: OH radical; Flash kinetic spectroscopy; Infrared laser; Absorption; Dipole moment function. (jhd)