Electron-Promoted Desorption from Water Ice Surfaces: Neutral Gas-Phase Products

Abdulgalil AGM, Rosu-Finsen A, Marchione D, Thrower JD, Collings MP, McCoustra MRS

Zusammenfassung

Electron-promoted desorption (EPD) from compact amorphous solid water (c-ASW) has been studied. Low-energy electron bombardment with 200–300 eV electrons leads to H2O depletion, as monitored by reflection–absorption infrared spectroscopy (RAIRS) of the remaining c-ASW film. Cross sections for H2O depletion were calculated to be in the range from 1.6 ± 1.0 × 10–16 to 5.2 ± 3.0 × 10–16 cm2. However, mass spectrometric measurements identify a major component of the desorbing material as H2, which appears with kinetics similar to those for H2O loss. Molecular H2O is observed as a minor desorption product in the gas phase.