Photoemission from Surface States on Tungsten

Abstract

Energy distribution spectra of photoelectrons emitted normal to a (100) plane of tungsten show a pronounced peak located 0.4 eV below the Fermi level, which is attributed to surface states. It is very sensitive to gas adsorption and disappears as the surface is saturated with hydrogen in the ${\ensuremath{\beta}}_{2}$ state, corresponding to a coverage of 2.5\ifmmode\times\else\texttimes\fi{}${10}^{14}$ molecules/${\mathrm{cm}}^{2}$.