Abstract
Secondary emission spectra from surface-state resonances in the [21¯1¯] and [112¯] azimuths of the silicon (111) 7×7 surface are discussed. The spectra extend to 6 eV above the vacuum level, with resonances with k=0 occurring at energies of 0.87±0.01 eV, 1.15±0.02 eV, and 3.5±0.1 eV above the vacuum level.