Wc. Simpson et al., DISSOCIATIVE ELECTRON-ATTACHMENT IN NANOSCALE ICE FILMS - THICKNESS AND CHARGE TRAPPING EFFECTS, The Journal of chemical physics, 108(12), 1998, pp. 5027-5034
The yield and kinetic energy (KE) distributions of D- ions produced vi
a dissociative electron attachment (DEA) resonances in nanoscale D2O i
ce films are collected as a function of film thickness. The B-2(1), (2
)A(1), and B-2(2) DEA resonances shift to higher energies and their D-
ion yields first increase and then decrease as the D2O films thicken.
The D- KE distributions also shift to higher energy with increasing f
ilm thickness. We interpret the changes in the DEA yield and the D- KE
distributions in terms of modifications in the electronic and geometr
ic structure of the surface of the film as it thickens. A small amount
of charge build-up occurs following prolonged electron beam exposure
at certain energies, which primarily affects the D- KE distributions.
Charge trapping measurements indicate that an enhancement in the trapp
ing cross section occurs at energies near zero and between 6 and 10 eV
. (C) 1998 American Institute of Physics.