Products of Sublimated Ammonium Salts

Abstract

Ammonium salts are increasingly suspected to play an important role in astrochemistry, as both a reservoir, particularly of sulfur and nitrogen, and a potential source of complex molecules, in spite of the lack of knowledge on their sublimation process and products. We have studied the sublimation of four ammonium salts using mass-selected photoelectron spectroscopy coupled to vacuum ultraviolet synchrotron radiation to identify most of the sublimation products. We show that, if proton transfer yields stable products without rearrangement, leading to NH₃ or CH₃NH₂, this route will be favored. Furthermore, we suggest that the sublimation of salts could lead to the formation of complex molecules, such as formamide, and also constitute a possible route for the formation of isonitriles.