Laser photolysis of ozone in the presence of ammonia: Vibrationally excited OH radicals

Abstract

Vibrationally excited OH radicals were generated by 266 nm laser photolysis of ozone in the presence of ammonia. Temporal profiles of OH(ν=0, 1, 2) concentrations were directly monitored by LIF techniques at various NH 3 pressures. The total vibrational distribution of OH product in the reaction O ( 1D)+ NH 3→NH 2+OH was found to be much hotter than the statistical distribution- P(ν=0): P(ν=1): P(ν=2): P(ν=3)=0.20:0.32:0.34:0.14. Vibrational relaxation rate constants of (2.1±0.3)× 10 −11, (1.0±0.3)×10 −10 and (3.0±1.0)×10 −10 cm 3/s were measured for collisions of OH(1), OH(2) and OH(3) with NH 3.