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Raman and Infrared Spectra of Tellurium Sub‐Bromide (Te 2 Br)
Author(s) -
Anastassakis E.,
Raptis J. S.,
Richter W.
Publication year - 1985
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.2221300113
Subject(s) - phonon , raman spectroscopy , tellurium , orthorhombic crystal system , infrared , wavelength , far infrared , spectral line , materials science , chemistry , atomic physics , analytical chemistry (journal) , optics , condensed matter physics , physics , optoelectronics , crystallography , crystal structure , inorganic chemistry , astronomy , chromatography
Abstract Raman and IR spectroscopic techniques are used to study the long‐wavelength optical phonons of tellurium sub‐bromide (orthorhombic structure). By use of an appropriate range of temperatures and excitation wavelengths the frequencies for nearly all of the A 2 and B 2 q ≈ 0 optical phonons are determined. Oscillator strengths and LO‐frequencies for these phonons are obtained from the fitting of IR reflection spectra with a multiple oscillator model. The temperature dependence of the frequency and damping constant for some of these phonons is discussed. A remarkable feature of this material is the existence of low frequency (≈ 20 cm −1 ) phonons with extremely large polarizabilities (Δ χ up to 150).