LEED and electron spectroscopic observations on NiO (100)

LEED, Auger, and electron-loss spectra are reported for a UHV-cleaved NiO (100) surface. Data are given for the clean surface and a surface contaminated mostly with about half a monolayer of chlorine. Large systematic intensity variations are found between different LEED beams, and the possibility of anisotropic electron mean free paths is suggested. The loss spectra are interpreted as containing features due to charge transfer excitons.