The laser-induced fluorescence technique has been employed to study the first excited electronic stated Ã2A1 of CH 3O. Vibrational levels v′3 = 0-7 of the Ã state were excited and fluorescence decay rates were measured. Compared to a value 2.2 ± 0.2 μs at V′3 = 0, a significant decrease of decay rate was found at 277.6 nm (0.89 μs, v′3 = 7). Excitation to higher levels further reduced the lifetime. The predissociation threshold was estimated to be slightly above 276 nm (36 220 cm-1). The electronic quenching rates of the Ã state (v′ = 0-2) by CH 3OH, O2, NO2, and N2 have also been determined and are compared with those of OH in the Ã state.