Quenching of OD (A 2Σ+,v′=0 and 1) by various gases

A tunable pulsed dye laser was used to pump OD to the (A 2∑+,v′=1) level. The fluorescence excitation spectrum of OD in the wavelength region 287.26–290.03 nm in the A→X system was recorded. The rate coefficients for quenching of OD (A 2∑+) from v′=0 and v′=1 levels by O2, N2, air, and SF6 were measured. The rate coefficient for vibrational relaxation of OD (A 2∑+) from v′=1 to v′=0 level was separated from the overall rate coefficient for quenching of OD (A 2∑+) from v′=1 level to the ground (X 2Π) state for the above four gases. The rate coefficients for quenching of OD (A 2∑+) from v′=0 level to the ground (X 2Π) state by 15 common gases were measured by using excess SF6 to rapidly quench the OD (A 2∑+) from v′=1 to v′=0 level. All measurements were carried out in excess helium and are for rotationally thermalized OD (A 2∑+) radicals.