The fine structure (FS) of the experimental absorbed (target or total) current spectra (ACS) along the normal to a clean ZrS2(0001) surface is interpreted theoretically. As before (see, e.g. [1-5]) during the calculation of ACS the electron scattering with a preset momentum at the crystal was considered within the approximation, when the probability of scattering was proportional to a number of finite states at a given energy level with a preset direction of quasi-momentum. It is shown that the FS of ACS is mainly due to the electronic structure of unoccupied high-level electronic states (above the vacuum level), which become occupied by electrons entering a solid. The predominant role of the bulk energy-band structure (BES) effects in the spectra formation is shown. The extrema in ACS reflect the energy position of the critical points in the unoccupied BES, such as band edges or extremal dispersion-branch curvature points. And there occurs a possibility for the experimental study of the electron dispersion in the region of energies much higher than the vacuum level (thus adding to the traditionally used data of the photoemission, inverse photoemission and optical spectroscopy). The method being developed enables one to distinguish between the volume effects in ACS from the surface ones, which are to be investigated separately. In addition, a comparison to existing theoretical and experimental data is given.
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[5] O.F. Panchenko, L.K. Panchenko, Surf. Sci. 600 (2006) 3830.
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