Fundamental Optical Functions and Fine-Structure Parameters of Strontium–Selenide Crystal Transition Bands in the 0–40 eV Range

Abstract

The spectral complex of fundamental optical functions of strontium-selenide (SrSe) crystal in the range 0–40 eV was determined. Spectra of the imaginary parts of three functions [transverse dielectric permittivity e2(E) and longitudinal volume –Im e–1 and surface –Im (1 + e)–1 characteristic electron energy losses] of SrSe crystal were deconvoluted into 36 elementary bands. Energies of maxima Ei, half-widths Hi, amplitudes Ii, areas Si, and oscillator strengths fi were determined for every band of the three spectra. The main spectral features of the optical functions and 36 elementary bands of SrSe in the range 3–35 eV due to excitons and transverse and longitudinal interband transitions were established. The calculations were based on experimental reflectance spectra and used the Kramers–Kronig integral relations, a modified combined Argand diagram method, and a number of computer programs.