Photodissociation of ethanolamine in interstellar clouds driven by UV and soft X-ray irradiation

ABSTRACT We investigate the photoinduced fragmentation of ethanolamine (EtA, C$_2$H$_7$NO), a prebiotically relevant amino alcohol detected in G+0.693–0.027, under ultraviolet (UV) and soft X-ray irradiation (12–310 eV) to explore its stability and chemical pathways in astrophysical environments. Experimental data were combined with Born–Oppenheimer molecular dynamics simulations, which revealed dominant fragmentation pathways and identified nitrogen-containing species as the major ionic products. Notably, ${\rm CH_2NH_2}^+$, a highly stable cation formed via C–C bond cleavage and charge localization on the nitrogen centre, emerged as a key fragment. While ${\rm CH_2NH_2}^+$ has not yet been detected in the interstellar medium, our results indicate it as a promising candidate for future astronomical searches. Calculated photoionization and photodissociation cross-sections enabled the estimation of photodissociation rates and half-lives for EtA under the X-ray conditions of Sgr B2. EtA exhibited a half-life on the order of $10^7$ yr, comparable to other complex organic molecules like methyl formate (HCOOCH$_3$) and acetic acid (CH$_3$COOH) but shorter than simpler molecules such as formic acid (HCOOH). These findings reinforce EtA as a key astrochemical molecule with significant potential for astrobiological implications.