Radiative lifetime and multiquantum vibrational relaxation of SO(B3Σ−, v′ = 3) by collisions with He

The time profiles of fluorescence from a single vibrational level of SO(B3Σ−, v′ = 3) were recorded at various He pressures. The radiative lifetime, 29 ± 4 ns determined by a deconvolution analysis, is nearly identical with those of v′ < 3. The rate coefficients for single-quantum relaxation, Δv = 1, and multiquantum relaxation Δv = 2 and 3, have been obtained from the He pressure dependence of dispersed fluorescence spectra. The Franck-Condon factors for v′ = 3 → v″ = 0-23 in the B3Σ−-X3Σ− system have also been determined.