3 B 1-1A1 transition of SO2 gas. II. Radiative lifetime and radiationless processes

A modification of the equation given by Strickler and Berg is derived for calculating from spectroscopic data the radiative lifetime of a molecule whose transition moment varies with configuration. Using this equation, the radiative rate constant of the 3B1 state of SO2 is calculated to be 79 ± 5 sec−1. The decay rate of this state is reported as a function of pressure at 30°C. The rate constant for quenching by ground state SO2 is found to be (4.52 ± 0.18) × 108 1 mole−1 · sec−1. The decay rate extrapolated to zero pressure is found to be (1.12 ± 0.20) × 103 sec−1. Comparison with the radiative rate constant shows that only about 7% of the triplet molecules emit, and the rest undergo some pressure independent nonradiative process.