Ionization of Water, Ammonia and Methane by Proton Collision: Experimental and Electronic Configuration Studies

The isoelectronic species water, ammonia and methane play an important role in the effects of ionizing radiation with profound implications in surrounding environments. The interest on these molecules remains unabated in diverse fields ranging from atmospheric and astro-chemistry to biomedical applications. The ionized molecules, their radicals and charged fragments are prolific sources for the formation and damage of organic compounds. In this study we present a short review of single ionization and fragmentation of water, ammonia and methane induced by swift proton collision. The formation of ionic species depends on the selection of which orbital electron(s) from the molecules are removed by the proton. The molecule is initially destabilized, then a stable, metastable or dissociative configuration state is reached. An ionic species is formed dependent on the excited state the molecule is left by the electron removal mechanism and its production can be attributed to several final ionic states. It is our goal to understand the mechanism of water, ammonia and methane dissociation based on the knowledge of the distribution of single primary vacancies produced by the swift proton collision. The electronic configuration and orbital symmetry of the molecule are playing a more dominant role in controlling the ionization and fragmentation processes.