QUANTUM YIELDS OF H(S-2) AND CH3S((2)E) FROM THE PHOTOLYSIS OF SIMPLEORGANOSULFUR COMPOUNDS AT 193-NM, 222-NM, AND 248-NM

The primary quantum yields for the formation of H(S-2), Phi(H), and CH 3S((2)E), Phi(CH3S), in the photodissociation of methyl mercaptan, dim ethyl sulfide (DMS), and dimethyl disulfide (DMDS) at the excimer lase r wavelengths of 193, 222, and 248 nm were measured. Phi(H) were measu red using resonance fluorescence detection of H atoms. The Phi(H) were 0.55 +/- 0.04 at 193 nm, 0.98 +/- 0.15 at 222 nm, and 1.09 +/- 0.25 a t 248 nm for methyl mercaptan; <0.02 at 222 nm and <0.03 at 193 nm for DMS; and <0.06 at 222 nm and <0.08 at 193 nm for DMDS. No H atom prod uction was observed in the 248 nm photolysis of DMS and DMDS. Using a selectively deuterated methyl mercaptan sample, CH3SD, it was shown th at C-H bond scission is negligible in CH3SH photolysis at 193 and 248 nm. The Phi(CH3S), measured by CH3S detection via pulsed laser-induced fluorescence, were 0.93 +/- 0.21 at 248 nn and 0.78 +/- 0.10 at 193 n m for DMS; 1.65 +/- 0.38 at 248 nm and 1.20 +/- 0.14 at 193 nm for DMD S; and 0.48 +/- 0.10 at 193 nm for methyl mercaptan. The nature of the photodissociation processes in these sulfur compounds is discussed in light of the present measurements and the results of past studies.