Electron Irradiation of Crystalline Nitrous Oxide Ice at Low Temperatures: Applications to Outer Solar System Planetary Science

The radiation chemistry and physics of solid N2O have been increasingly studied due to its potential presence on the surfaces of cold, outer Solar System bodies. However, to date, no study has investigated systematically the influence of temperature on this chemistry and physics. In this present study, crystalline N2O ices were irradiated using 2 keV electrons at five different temperatures in the 20-60 K range and the radiolytic dissociation of the molecular solid (as well as the radiolytic formation of seven product molecules) was quantified through the G-value. Our results indicate that temperature does indeed play a role in the radiolytic destruction of crystalline N2O, with higher temperatures being associated with higher destruction G-values. The formation G-values of NO, NO2, N2O2, N2O3, N2O4, N2O5, and O3 were also noted to vary with temperature, with each product molecule exhibiting a distinct trend. The applications of our experimental results to further understanding solid-phase radiation chemistry in the outer Solar System are discussed.