Explosive desorption from solid methane and methane-containing argon matrices

Abstract

The total yield of emitted particles from solid CH4 and Ar matrices doped with CH4 was studied under irradiation with electrons. The explosive desorption was detected for these systems. Strong bursts of particles were delayed with respect to the start of irradiation indicating the need for accumulation of radiolysis products. The study was performed using optical and current spectroscopy – cathodoluminescence (CL) together with thermally stimulated exoelectron emission (TSEE) and thermally stimulated post-desorption (TSpD). In the CL spectra, the products of radiation-induced transformation of CH4 molecules were recorded: H, CH, C. Dose dependencies of the optical emissions were measured in a correlated manner with the total yield of particles. It was found that the particles burst correlates with an increase in the concentration of H atoms. Scenario suggested for the delayed particle emission incorporates the recombination of CH3 radicals appearing simultaneously with H atoms in the reaction CH4 → CH3 + H.