E(K) OF Ni ABOVE THE VACUUM LEVEL AS MEASURED BY VLEED ON RELAXED (110) SURFACE

Varying incidence angle, VLEED spectra R(E) and dR/dE were measured on Ni(110) using target current technique. The results were interpreted with the reference spectra calculated on the basis of ground-state band structure. Some critical points (CPs) of E(k) displayed themselves as dR/dE extremums while others remained invisible. Changing of incidence K|| by a surface reciprocal vector switched manifesting CPs. Experimental CPs were determined by comparing energies of experimental dR/dE extremums with. their reference counterparts. Having mapped CPs along a variety of non-symmetry directions, bands along ΓX were constructed. Experimental E(k) is consistent with other experimental data and APW calculations. Some peculiarities are attributed to the influence of surface relaxation. Capabilities of VLEED to provide PES with upper bands are discussed.