Photochemistry of carbon monoxide and methanol in water and nitric acid hydrate ices: A NEXAFS study
Publikation/Tidskrift/Serie: Physical Chemistry Chemical Physics
Förlag: Royal Soc Chemistry
Soft X-ray induced chemistry of H2O, CO and CH3OH and the effects of the water and nitric acid hydrate (HNO3 center dot 1.65H(2)O) matrix on the photochemistry of CO and CH3OH have been investigated using NEXAFS spectroscopy. For pure H2O, CO and CH3OH ices, we show that the destruction rates are strongly limited by back reactions, leading to strikingly high survival rates of these molecules upon the harsh irradiation conditions to which they are submitted. We also evidence the interplay between the photochemical reactions of CO and CH3OH and those of the matrix. The OH and O radicals released by the photolysis of H2O and HNO3 react with the CO and CH3OH and their fragments, considerably reducing the survival rates compared to pure CO and pure CH3OH ices, especially in presence of nitric acid, and dramatically enhancing the formation of CO2 at the expense of CO. Because NEXAFS spectroscopy allows identifying which reactions are important among those possible, it emerges a simple picture of the photochemical routes of CO and CH3OH in the H2O and HNO3/H2O environments.
- Physics and Astronomy
- ISSN: 1463-9076