Photochemical flux of ammonia and glycine from N2O and its implication for origin of life

Abstract:

Abiotic formation of ammonia and amino acids are important for origin of life and its early evolution. Besides N₂, nitrous oxide (N₂O) could be a candidate for nitrogen source to synthesize ammonia (NH₃), because N₂O is the second abundant nitrogen species in the atmosphere. In this study, we report a new photochemical experiment to evaluate whether N₂O can be used as a nitrogen source to produce NH₃ and other organic nitrogen species. We conducted a series of experiments starting from a gas mixture of N₂O and CO or N₂O and CO₂ with the presence of liquid water under the irradiation of ultraviolet light with solar-like broad spectrum. The results demonstrated that NH₃, methylamine (CH₃NH₂) and some amino acids such as glycine and alanine can be synthesized through photochemistry from N₂O even without metal catalysts. We also conducted a photochemical model to simulate the reaction pathway, and we will calculate the production rate of glycine from a prebiotic atmospheres, in order to evaluate its contribution to the origin of life on terrestrial planets.