Simulation of HCS containing gas mixtures relevant to diamond chemical vapour deposition

Experimental and Computational Studies of the Kinetics of the Reaction of Atomic Hydrogen with Methanethiol

“…3 Here we focus on one of the simplest compounds, methanethiol, and its bimolecular reaction with atomic hydrogen…”

“…These include H atom abstraction from the SH group (R1.1), H atom abstraction from the CH 3 group (R1.2), breaking the C−S bond and displacing the CH 3 group (R1. 3), and cleavage of the C−S bond and displacing the SH group (R1.4): The thermochemistry of these pathways is summarized in Table 1. High-accuracy enthalpies of formation are available for H, CH 3 , and CH 4 from the Active Thermochemical Tables 10 and for H 12 Another aim of the work is to investigate the product branching ratios by computational methods.…”

“…3), and cleavage of the C−S bond and displacing the SH group (R1.4): The thermochemistry of these pathways is summarized in Table 1. High-accuracy enthalpies of formation are available for H, CH 3 , and CH 4 from the Active Thermochemical Tables 10 and for H 12 Another aim of the work is to investigate the product branching ratios by computational methods. There has been an initial theoretical study of three of these channels by Wang et al, who employed G3(MP2) energies and deduced that channel R1.1 was the major pathway.…”

“…27,28 Variation of [CH 3 SH] allows k to be separated from diffusion effects, and k is obtained as the slope of plots of k ps1 vs [CH 3 SH] like that shown in Figure 1. Weighted linear leastsquares fits to the k ps1 vs [CH 3 SH] plots, which take into account the horizontal and vertical error bars, are used to determine the second-order rate constant k, along with its statistical 1σ error. Table 2 summarizes 35 determinations of k, each from five different methanethiol concentrations, with the largest value tabulated.…”

“…Apart from changing the temperature T, we emphasized variation of the experimental parameters τ, the average residence time inside the heated reactor before Figure 1. Determination of the second-order rate constant k by plotting k ps1 with 2σ error bars obtained from each pseudo-first-order decay against [CH 3 SH]. The inset shows the decay from the first k ps1 point.…”