Kinetic studies of atomic carbon, C[2p2(3PJ)], with thiols by time-resolved atomic resonance absorption spectroscopy in the vacuum ultraviolet

Reaction rates of atomic carbon in its electronic ground state, C[2p(2)(P-3(J))], with a range of large sulfur-containing molecules have been investigated using time-resolved atomic spectroscopy in the vacuum ultraviolet following pulsed irradiation. Absolute rate data for the collisional removal at 300 K of C(2(3)P(J)) by the gases 1-propanethiol, 1-butanethiol, 1-pentanethiol, 2-propanethiol, 2-methyl-l-propanethiol, 2-methyl-2-propanethiol and dimethyl sulfide are reported. All processes proceed at rates of the order of the collision numbers, supporting an overall mechanism of C-atom insertion into the S-H bond following initial addition, which is energetically favourable, a mechanism demonstrated analogously hitherto with H2S and where H-atom abstraction would also be endothermic.