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The Temperature Dependence of Absorption of Sodium Nitrite in the Far Infrared
Author(s) -
Vogt H.,
Happ H.
Publication year - 1968
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.19680300108
Subject(s) - absorption (acoustics) , ferroelectricity , halide , atmospheric temperature range , chemistry , infrared , crystal (programming language) , alkali metal , far infrared , phonon , dielectric , lattice (music) , condensed matter physics , materials science , analytical chemistry (journal) , inorganic chemistry , thermodynamics , optics , physics , optoelectronics , organic chemistry , chromatography , computer science , acoustics , composite material , programming language
The paper deals with the infrared absorption of ferroelectric NaNO 2 in the wavelength range between 350 and 1100 μm. The observed temperature dependence of absorption is attributed to one‐ and multiphonon processes. Below 400 °K most of the measured isochromates can be approximately described by the relation x = A T + B T 2 known from multiphonon absorption in alkali halides. In the temperature range above 400 °K one expects additional defect‐induced one‐phonon absorption, because the onset of orientational disorder disturbes the translational symmetry of the crystal lattice. It is tried to explain the anomalies occurring in some isochromates about 450 °K by opposite temperature behaviour of one‐ and multiphonon absorption. In the paraelectric phase isotherms deduced from the isochromates show selective absorption, which appears most distinctly in the ferroelectric b ‐direction.