Clean and O2 adsorbed (001) surfaces were investigated using metastable impact electron spectroscopy and ultra-violet photo-electron spectroscopy. Two structures appeared close to the Fermi level EF and 3eV below it in the MIE spectrum of the clean (001) surface (work function: 2.3eV), and could be assigned to the La(5d) and dangling bond of B(2p), respectively. The peak near to EF originated mainly from an auto-detachment process between He*(1s2s) and La(5d). The results suggested that the clean (001) surface was terminated by La. Particular emphasis was paid to changes in these spectral featured as a function of oxygen exposure. Both structures disappeared at 1.5L. It was concluded that O2 was dissociated at the La-terminated surfaces. Two oxygen-induced peaks appeared in the metastable impact electron spectra and ultra-violet photo-electron spectroscopy spectra at 5.8 and 7.5eV binding energies. It was concluded that O2 was dissociated at the La-terminated surfaces.

Interaction of O2 with LaB6(001) Surfaces as Studied with MIES and UPS. Kawanowa, H., Souda, R., Otani, S., Ikeuchi, T., Gotoh, Y., Stracke, P., Krischok, S., Kempter, V.: Surface Science, 2001, 482-485[1], 250-3