Radiation-induced synthesis of formic acid in the H2O–CO system: A matrix isolation study
X-radiolysis of the noble-gas matrices containing both H2O and CO was investigated at 5 K using infrared spectroscopy. It was found that formic acid molecule (HCOOH) could be produced from the matrix-isolated H2O⋯CO complexes, either directly as a result of irradiation or upon the subsequent annealing activating the trans-HOCO + H reaction. The former way was observed in Kr, while the latter one in Xe matrix. Matrix-specific behavior and possible astrochemical implications are discussed.