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Infrared Vibrational Modes and Anisotropy of the Effective Ionic Charge in CuAlSe 2 , CuAlS 2 , and CuGaSe 2 Crystals
Author(s) -
Andriesh A. M.,
Syrbu N. N.,
Iovu M. S.,
Tazlavan V. E.
Publication year - 1995
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.2221870107
Subject(s) - anisotropy , phonon , ionic bonding , limiting , polarization (electrochemistry) , effective nuclear charge , ion , infrared , dielectric , spectral line , ionic crystal , dispersion (optics) , infrared spectroscopy , dispersion relation , materials science , chemistry , molecular physics , condensed matter physics , optics , physics , optoelectronics , quantum mechanics , mechanical engineering , organic chemistry , engineering
Abstract Reflectivity spectra of CuAlS 2 , CuAlSe 2 , and CuGaSe 2 crystals have been investigated in the wave number range 50 to 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 Cu, Al, Ga, Se, S anions and cations have been calculated in dependence on the incident light polarization.