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Dielectric Properties of the Rubidium Halide Crystals in the Extreme Ultraviolet up to 30 eV
Author(s) -
Peimann C. J.,
Skibowski M.
Publication year - 1971
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220460223
Subject(s) - atomic physics , excited state , core electron , electron , chemistry , photon energy , exciton , valence electron , photon , condensed matter physics , optics , physics , quantum mechanics
The reflectivity of freshly cleaved single crystals of RbCl, RbBr, and RbI and of an evaporated RbF film was measured at room temperature for photon energies between 10 and 30 eV using synchrotron radiation. With a resolution of 2 Å over the whole spectral range considerable new spectral features were observed in the region where high energy valence band transitions occur and electrons from the first core level, the Rb + 4p level, are excited. For all Rb halides excitation of the Rb + 4p level starts at about 16 eV with an exciton multiplet which can be explained as being due to spin‐orbit splitting of the core level and to critical points at Γ and X in the conduction band. The energies of the multiplet are compared to transition energies of the 4p electrons of the free Rb + ion. The complex dielectric constant, the absorption coefficient, and the energy loss function are derived from the reflectivity by means of a dispersion analysis. The results are compared with absorption and electron energy loss experiments on evaporated polycrystalline films.