Laser-induced fluorescence studies of the CH3S radical
Abstract
Methylthio radicals (CH3S) have been generated by the 248 nm photodissociation of dimethyl disulphide [(CH3S)2] and 193 nm photodissociation of methylmercaptan [CH3SH]. Fluorescence has been excited on the Ã2A1â†�X2E transition. The transitions excited were 320 at 366.0 nm, 310 at 371.3 nm and 000 at 377.0 nm. Vibrational relaxation and electronic quenching of the upper state have been studied with a number of gases. By varying the delay between the excimer and dye laser pulses, it has also been possible to study vibrational relaxation in the ground state in the presence of the same gases. No reaction of the CH3S radical could be found with either O2 or O3(kO3⩽ 8 × 10–14 cm3 molecule–1 s–1), although the fast reaction with NO2 was confirmed.