Fluorescence from S2 single vibronic levels in thiophosgene vapor: Quantum yields and quenching effects

Abstract
The quantum yields of fluorescence from the second excited singlet state of thiophosgene vapor have been measured as a function of pressure for eight S2S0 transitions, and parameters for the decay of the levels pumped have been calculated. The results indicate that reassignment of the origin of the S2S0 band system to 35 112 from 36 007 cm−1 is necessary. Quantum yields of fluorescence from the lowest levels in S2 are extremely high (0.50 to 1.0) and are indicative of a very slow radiationless decay rate. Weakening of fluorescence from higher S2 vibrational levels is most likely caused by predissociation.