Electron- and positron-driven molecular processes for H2O, CO2, and NH3 in their gas and ice phases

Abstract

In this comprehensive study, we explored the molecular chemistry of H₂O, CO₂, and NH₃ molecules in their gas and ice phases assisted by electron and positron interactions over a wide range of energy from threshold to 5000 eV. These simple molecules have immense applications in areas such as atmospheric sciences and astrochemistry. We employed the spherical complex optical potential (SCOP) model along with the complex scattering potential-ionization contribution (CSP-ic) model and modified them to quantify the probabilities of various charged particle-driven molecular processes through inelastic cross-sections (Q_inel), total ionization cross-sections (Q_ion), direct ionization cross-sections (Q_D-ion), and positronium formation cross-sections (Q_Ps) for these molecules in gas and ice phases. We propose a novel model that incorporates the band gap of a material for positron impact cross-sections with molecules in their condensed phase. This is the first study on electron interactions with NH₃ (ice) and positron interactions with H₂O, CO₂, and NH₃ in their condensed phase.