Experimental Simulation of Fast Electron Bombardment of Methanol Ice and Its Implications in Astrochemistry

Abstract

In this work, we experimentally simulate the methanol (CH3OH) ice behavior (12 K) through the bombarded by fast electrons (4.9 keV) in an attempt to simulate radiation chemistry induced by radiation in space environments. The sample analysis by infrared spectroscopy reveals the appearance of new species, including CO2, CO, H2O, and CH4, during the sample bombardment. We have quantified the effective destruction cross-section of methanol (5.5 × 10-19 cm2) and determined the formation cross-section for these newly produced species. Additionally, we have characterized the chemical equilibrium (CE) phase, which becomes evident at higher fluences. We have also calculated molecular abundances and assessed the desorption yield induced by fast electrons within the same sample. Furthermore, we estimated the timescale required to achieve chemical equilibrium in specific astrophysical environments impacted by electrons. This study significantly contributes to our comprehension of electron bombardment behavior in astrophysical ices and allows for meaningful comparisons with organic-rich ices in space environments