The Effect of Electron Bombardment on Isotopic Water Adsorbed on Zr(0001) Surfaces
Abstract
A study of the effect of electron bombardment on water adsorbed on Zr(0001) is carried out using an ultra-high vacuum (UHV) chamber. Clean Zr(0001) surfaces are dosed with isotopic water at 160 K followed by electron bombardment (energy about 500 eV). The system is then probed by low energy electron diffraction (LEED), temperature programmed desorption (TPD) and Auger electron spectroscopy (AES). Isotopic water is used to determine whether hydrogen from within the subsurface mixes with isotopic water dissociation products (deuterium) on the surface during TPD, and no evidence of this is found. However, electron bombardment results in the formation of a hydrogen/deuterium desorption peak near 320 K which is not seen in the absence of electron excitation. In both cases, following TPD, clean surface LEED patterns and AES spectra are recovered by annealing to dissolve residual oxygen into the bulk. In addition, although water does not oxidize Zr(0001) thermally, electron bombardment of adsorbed water induces a shift of about 2 eV in the Zr AES features indicating that the surface is partially oxidized by hyperthermal processes.
- Publication:
-
APS Ohio Sections Spring Meeting Abstracts
- Pub Date:
- April 2002
- Bibcode:
- 2002APS..OSS.B1011A