Efficient Surface Formation Route of Interstellar Hydroxylamine through NO Hydrogenation II: the multilayer regime in interstellar relevant ices

摘要

Hydroxylamine (NH2OH) is one of the potential precursors of complexpre-biotic species in space. Here we present a detailed experimental study ofhydroxylamine formation through nitric oxide (NO) surface hydrogenation forastronomically relevant conditions. The aim of this work is to investigatehydroxylamine formation efficiencies in polar (water-rich) and non-polar(carbon monoxide-rich) interstellar ice analogues. A complex reaction networkinvolving both final (N2O, NH2OH) and intermediate (HNO, NH2O, etc.) productsis discussed. The main conclusion is that hydroxylamine formation takes placevia a fast and barrierless mechanism and it is found to be even more abundantlyformed in a water-rich environment at lower temperatures. In parallel, weexperimentally verify the non-formation of hydroxylamine upon UV photolysis ofNO ice at cryogenic temperatures as well as the non-detection of NC- andNCO-bond bearing species after UV processing of NO in carbon monoxide-richices. Our results are implemented into an astrochemical reaction model, whichshows that NH2OH is abundant in the solid phase under dark molecular cloudconditions. Once NH2OH desorbs from the ice grains, it becomes available toform more complex species (e.g., glycine and beta-alanine) in gas phasereaction schemes.