Time-resolved thermal lensing studies on metastable species

摘要

Time-resolved thermal lensing (TRTL) techniques have been applied to resolve photophysical and thermodynamic parameters forvarious metastable species, of which the relaxation dynamics are dominated by the radiationless transition. Using 1H-phenalen-1-one as a sensitizer, the lifetime (iota(Delta)), absolute quantum yield (Phi(Delta)) and efficiency of generation (S-Delta(T)) of singlet molecular oxygen ((1)Delta(g)) have been determined in various organic solvents. In particular, through the development of an ultrasensitive detecting system, TRTL studies on the relaxation dynamics of O-2((1)Delta(g)) become feasible in aqueous solution. In another application, based on the TRTL technique in combination with the O-2 sensitization experiment, the T-1-S-0 energy gap of the proton-transfer tautomer in 3-hydroxyflavone, which is otherwise inaccessible due to the dominant radiationless deactivation, has been deduced to be similar to 8500 +/- 1020 cm(-1). [References: 46]