Dynamics of the Reaction S(¹D) + HD, H₂, and D₂: Isotopic Branching Ratios and Translational Energy Release

Abstract

Doppler profiles of H and D atoms from the reaction S(tD) with HD and a mixture of H and Dz have been measured by a laser-induced fluorescence technique with a vacuum ultraviolet laser. An isotopic channel branching ratio of q, (SD + H)/, (SH + D) is measured to be 0.9 + 0.1 in the reaction of S(ID) + HD at average collision energy Ecol 1.2 kcal/mol. In S(D) + HD, D z, and Hz, the translational energies released are almost the same, 4.6 _+ 0.5 kcal/mol for H and D production channels. The measured branching ratio and translational energy release suggest that the reaction proceeds via a long-lived complex formed by insertion.

Potential Energy Surface for Ground-State H2S via Scaling of the External Correlation, Comparison with Extrapolation to Complete Basis Set Limit, and Use in Reaction Dynamics

“…Following ref 27, this is accomplished by using the switching function with the parameters in g(r 1 ) being chosen such as to warrant that its main effect occurs for S-H 2 distances larger than 8a 0 or so (see the right-hand side panel of Figure 1 in the Supporting Information). In turn, the parameters in h(R 1 ) are calibrated from a least-squares fit to an extra set of 10 AVQZ points that control the S( 1 D) -S( 3 P) decay with a growing H-H distance (see the left-hand side panel of Figure 1 in the Supporting Information).…”

“…Specifically, the reactions of S( 1 D) with H 2 and its isotopomers are known to proceed via an insertion pathway, as demonstrated in many experimental observations [1][2][3][4] and theoretical work. [5][6][7][8][9][10][11][12] In a series of experiments, Inagaki et al .…”

Rate coefficients from quantum and quasi-classical cumulative reaction probabilities for the S(1D) + H2 reaction

“…The S( 1 D) + H 2 (X 1 + g ) → SH + H reaction has been widely studied, both experimentally [24][25][26][27] and theoretically. [28][29][30][31][32][33][34][35][36][37][38][39][40][41] Given the vast amount of available information, the system has become a benchmark for insertion, barrierless reactions.…”

Theoretical study of the multiplet branching of the SD product in the S(D1)+D2→SD(Π2)+D reaction

“…Experimental studies of the dynamics of this reaction [34][35][36][37][38] have been less numerous than studies of the analogous O͑ 1 D͒ +H 2 reaction. In a series of crossed molecular beam experiments, Lee and Liu [35][36][37] investigated the S͑ 1 D͒ +H 2 , D 2 , and HD reactions through Doppler-selected time-of-flight detection of the H or D product.…”