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Infrared vibrational Modes in Tl 3 SbS 3 , Tl 3 AsS 3 , and Tl 3 AsSe 3 crystals
Author(s) -
Syrbu N. N.,
Krasovsky V. T.,
Grincheshen I. N.
Publication year - 1994
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.2170290811
Subject(s) - limiting , polarization (electrochemistry) , phonon , dielectric , infrared , spectral line , reflectivity , ion , dispersion (optics) , infrared spectroscopy , dispersion relation , chemistry , materials science , atomic physics , optics , analytical chemistry (journal) , condensed matter physics , physics , optoelectronics , quantum mechanics , mechanical engineering , organic chemistry , chromatography , engineering
Reflectivity spectra of Tl 3 SbS 3 , Tl 3 AsS 3 , and Tl 3 AsSe 3 crystals have been investigated in the wave number range 50–600 cm −1 for the polarizations E ∥ c and E ⟂ c . The fundamental phonon parameters, the limiting dielectric constants ϵ ∞ and ϵ S and the reflectivity spectra contours have been calculated by using classical dispersion relations for both E ∥ c and E ⟂ c configurations. The Szigeti effective charges and the relative ion charges of As, Tl, Sb, Se, S anions and cations have been calculated in dependence on the incident light polarization.