Electron stimulated desorption via dissociative attachment in amorphous H2O

Abstract

Low energy (0–12 eV) electron impact on condensed amorphous H2O and D2O films is shown to induce electron stimulated desorption of H− and D−, respectively, via dissociative electron attachment. The onsets for H− and D− detection are at 5.5 eV, with a maximum yield for anion desorption at ∼7.4 eV. The kinetic energy distributions of the desorbing anions are peaked near 0 eV, indicating that the anions suffer post-dissociation collisions at or near the surface, with a large probability of anion trapping on the surface. The present results provide direct information on the dissociation products, prior to the interferences of subsequent reaction processes in the condensed film.