AG(111) ELECTRON BAND-STRUCTURE AND CHANNELING BY VLEED

Very-low energy electron diffraction (VLEED) provides useful evidence about the electron band structure of crystal surfaces above the vacuum level. The intensity of the normally incident beam has been measured in detail for Ag(111) in the range 5-35 eV by a low-energy electron mi croscope. A sharp resonance, as found for Cu(111) [I. Bartos, M.A. Van Hove, M.S. Altman, Surf. Sci. 352-354 (1996) 660] below the Bragg pea k, is connected with the local energy band gap. Good agreement of the I-V curves with theoretical calculations is obtained (in particular th e small width of the resonance) when electron channeling along the sur face is taken into account. (C) 1998 Elsevier Science B.V. All rights reserved.