Exploiting single photon vacuum ultraviolet photoionization to unravel the synthesis of complex organic molecules in interstellar ices

⿢The ISM is rich with COMs, but gas phase models cannot explain their formation routes.⿢Experiments analogous to synthesis on grains by the exposure of ISM ices to radiation.⿢PI-ReTOF-MS is exploited to selectively identify COMs isomers.⿢COMs are synthesized via non-equilibrium chemistry inside ISM ices as cold as 5 K.⿢Experiments constrain the complexity of molecules that are formed in the ISM.