Measurement of the Natural Lifetimes and Quenching Rate Constants of OH(2Σ+, v = 0,1) and OD(2Σ+, v = 0,1) Radicals

Abstract

The lifetimes of OH(2Σ+) and OD(2Σ+) radicals were measured by using pulse-photolysis of water and methanol in the vacuum-uv for the production of the electronically excited radicals. From the fluorescence decay measurements the natural lifetimes, as well as the quenching rate constants for several added gases such as H2O, CH3OH, H2, N2, Ar, and He were determined. In particular, the natural lifetime of OH (2Σ+, v = 0), τ = (1.00 ± 0.06) · 10-6 s, was corrected for rotation-vibration as well as for rotation-electronic interactions resulting in a lifetime of (0.83 ± 0.08) · 10-6 s for the rotationless state. A lifetime of (0.82 ± 0.08) · 10-6 s was derived for the rotationless state of OD(2Σ+,v = 0).