Rotational dependence of the quenching of electronically excited CH(A 2Δ) and CH (B 2Σ −) produced by laser photolysis of acetone at 193 nm

Abstract

Electronic relaxation rate constants for specific rotational levels of CH(A 2Δ and B 2Σ −) have been measured. In contrast to similar measurements made earlier for other hydrides, the results obtained in the present work show an increase in the quenching efficiency upon rotational excitation. The electronically excited CH states are produced by multiphoton excitation and fragmentation of acetone upon photolysis at 193 nm by means of an ArF excimer laser light. The CG fragments are produced rotationally hot and the time evolution of rotational levels with N′⩽21 for CH(A 2Δ, v′=0) and N′⩽15 for CH(B 2Σ −, v′=0) can be measured.