The co-adsorption properties of Cs and oxygen on (100) and (110) were investigated using Auger electron spectroscopy and the FERP method of work function measurement. It was found that adsorption of Cs on the clean surfaces results in work function minima φm of 1.97 and 1.88eV for the (100) and (110) surfaces, respectively, whereas Cs adsorption onto the surfaces with pre-adsorbed oxygen resulted in φm values of 1.35 and 1.47eV. Auger data suggested that oxygen adsorbed preferentially at B sites, but that La surface atoms were involved in the bonding. Oxygen precoverage increased the ionic character of the Cs bond as well as the Cs coverage at φm. At room temperature there was no evidence of multilayer Cs adsorption.

Cesium and Oxygen Coadsorption on LaB6, Single Crystal Surfaces. I. Work Function Change. Chambers, S.A., Davis, P.R., Swanson, L.W., Gesley, M.A.: Surface Science, 1982, 118[1-2], 75-92