Wavelength resolved UV photodesorption and photochemistry of CO2 ice

摘要: Over the last four years we have illustrated potential of a novel wavelength-dependent approach in determining molecular processes at work photodesorption interstellar ice analogs. This method, utilizing unique beam characteristics vacuum UV beamline DESIRS French synchrotron facility SOLEIL, has revealed an efficient indirect desorption mechanism that scales with electronic excitations solids. process, known as DIET – induced by transition occurs efficiently ices composed very volatile species (CO, N2), for which photochemical can be neglected. In present study, investigate energy dependence pure and pre-irradiated CO2 10–40 K between 7 14 eV. The from is limited to photon energies above 10.5 eV clearly initiated excitation contribution dissociative recombination channels. “pre-irradiated” shown additional pathway below 10 eV, dominating depending on UV-processing history film. effect identified process mediated photoproduced CO, observed first time case less species. results presented here pinpoint importance interconnection driven photons having different energies.