Examining the isotope effect on CH decay and H exchange reactions: H(2S) + CH(D/T)(2Π)

Abstract

Abstract The influence of the isotope substitution on the H + CH(D, T) reactions is analyzed in detail by the method of quasi-classical trajectory on the CH 2 ( X ˜ 3 A ″ ) potential energy surface. By calculating the integral cross sections (ICSs), rate constants, and product vibrational and rotational state resolved ICSs, we find that when the isotope substitution effect promotes the R1 (CH decay) reaction, it can inhibit the R2 (H exchange) reaction. The analysis of differential cross sections (DCSs) indicates that H + CH(D/T) for R1 reaction is dominated by indirect reaction mechanism in the lower collision energy region, and governed by direct reaction mechanism in the high collision energy region. Finally, the calculated distributions of P(θ r ) and P(ϕ r ) show that the product rotational angular momentum j ′ is slightly oriented along the positive y-axis for R1 reaction, but for R2 reaction, there are no clear peak structures, so the polarization is not significant.