Modeling electron beam irradiation of methane

We built a chemical kinetic model for the electron beam irradiation of methane and report simulation results with dose rates ranging from 2 to 200 kGy s–1 at 298 K and 1 atm pressure. The model contains 92 species and 778 gas‐phase reactions. We report the time evolution of concentrations of stable products (including H2, C2H6, C3H8, C2H4, C3H6, C4H10, C2H2, and C3H4) as well as some radicals and ions. We discuss how yields of products depend on dose rate and how they change during the course of irradiation. To understand the processes controlling product formation, we quantify the extent to which various reactions produce and destroy major products and the key radicals and ions. Normalized sensitivity coefficients are computed for the production of stable products to gain further insight into factors controlling product yields. We were able to reduce the mechanism to 63 species and 331 reactions while incurring less than 5% error in the final concentrations of stable products.