Electron-stimulated ion and neutral desorption from D2O adsorbed on rare-gas–solid substrates

Electronic excitation induces explosive desorption of D2O molecules in nanoclusters formed on rare-gas–solid substrates as a result of Coulombic repulsion between confined valence holes. Cluster ions are ejected from D2O in the form of solvated deuteron [D+(D2O)n, n=1–10] and the ion yields decay with increasing coverage. A quite similar behavior is observed for desorption of neutral D2O molecules, indicating that D2O desorbs via the Coulombic repulsion followed by neutralization on the way out from the surface. The thick D2O ice is rather stable against electron-beam irradiation because of the delocalization of nascent valence holes and the formation of stable hydronium ions.