Threefold Differential Electron-Stimulated Desorption Yields of D^- Anions from Multilayer Films of D₂O and ND₃ Condensed on Platinum

Abstract

Dissociative electron attachment (DEA) processes have been observed for multilayer films of D2O and ND3 condensed on polycrystalline platinum at 20 K. Kinetic energy distributions, fixed kinetic energy anion yields, and angular repartitions for D- anions are reported for primary electron energies from 5 to 15 eV. No trace of any other fragment anion was detected. Comparison with gas phase D- differential cross sections shows that the dynamics of dissociation and desorption processes is strongly perturbed in the condensed phase both by the polarizability of the adsorbate and the metallic substrate and by the transfer of excess energy to the lattice acting as a cooling bath. Moreover, the low-energy desorbing anion fragments are very sensitive to charging effects at the dielectric surface.