Transient spectra and primary processes in the flash photolysis of CH3SSCH3, CH3SCH3, CH3SH and C2H5SH

Abstract

From direct observation of the CH₃, CH₃S, CH₂S and S₂ produced in the flash photolysis of CH₃SSCH₃(∼1950 Å) it was concluded that the primary processes are : [graphic ommitted] The relative degree of S—S to C—S bond scission was recorded as ∼1.35. The stability of CH₃S and the instability of CH₃SS are consistent with statistical partitioning of the excess energy.

From the independence of the CH₃S and CH₃ on total pressure in the ∼1950 Å flash photolysis of CH₃SCH₃, it was concluded that the primary process is predominantly CH₃SCH₃+hν→CH₃+CH₃S. The stability of the generated CH₃S is consistent with the statistical energy partitioning. By assuming equal yields of CH₃ and CH₃S radicals, the oscillator strength of the CH₃S band at 2185 Å was 1.3(±0.2)× 10^–3.

Two primary processes were identified in the ∼1950 Å flash photolysis of CH₃SH, [graphic ommitted] and the relative degree of C—S to S—H bond cleavage was 1:1.7. It was suggested that in this case the excited CH₃SH finds a configuration in which the S—H potential is repulsive more rapidly than the rate at which the energy is partitioned. To account for the pressure dependent formation of CH₃ and CH₂S in the ∼1950 Å flash photolysis of C₂H₅SH, and also the independence of CH₂S on added nitric oxide, the primary processes [graphic ommitted] were postulated.