BRANCHING RATIOS FOR HYDROGEN-TRANSFER IN THE REACTIONS OF OD RADICALS WITH CH3SCH3 AND CH3SC2H5

Laser flash photolysis of DNO3/RSR'/R''H/N2 mixtures (R=CH3, R'=CH3 or C2H5, R''=n-hexyl or cyclohexyl) has been coupled with HDO detection by time-resolved tunable diode laser absorption spectroscopy to direct ly investigate the importance of C-H bond cleavage as the O2-independe nt pathway for the atmospherically interesting reactions of OD radical s with CH3SCH3 and CH3SC2H5. For both reactions the HDO yield is found to be approximately 0.84 +/- 0.15 (uncertainty is 2sigma), thus demon strating conclusively that C-H bond cleavage predominates over C-S bon d cleavage as a reaction pathway in the absence of O2.