The goal of our experiments is to elucidate the role of electrons in the synthesis of prebiotic molecules in cosmic (interstellar, planetary, and cometary) ices. Ammonia is of particular interest because it is the most abundant nitrogen-containing compound in the interstellar medium (ISM). Cosmic ices are subject to many forms of high-energy radiation (e.g., cosmic rays and g-rays). The resulting cascade of low-energy (&lt;20 eV) secondary electrons are thought to initiate radiolysis reactions in the condensed phase. Our goal is to simulate these processes in an ultrahigh vacuum chamber by dosing thin films of condensed ammonia onto a metal substrate. Using post-irradiation temperature-programmed desorption (TPD) experiments, we have found evidence for the electron-induced formation of hydrazine (N2H4) and diazene (N2H2) from ammonia. We have investigated the reaction yield dependence on film thickness, irradiation time, incident current, and metal substrate. These results provide a basis from which we can begin to understand the mechanisms by which ammonia can form more complex species in cosmic ices.

Ammonia radiolysis: An interstellar source of nitrogen

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.