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Temperature dependence of line width of SO 4 2− modes in the Raman spectra of ammonium sulphate
Author(s) -
Bajpai P. K.,
Jain Y. S.,
Bist H. D.
Publication year - 1990
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.1250210602
Subject(s) - raman spectroscopy , full width at half maximum , phonon , ion , line width , spins , ammonium , chemistry , spectral line , coupling (piping) , ferroelectricity , crystal (programming language) , condensed matter physics , polarization (electrochemistry) , analytical chemistry (journal) , molecular physics , atomic physics , materials science , optics , physics , dielectric , optoelectronics , organic chemistry , chromatography , astronomy , computer science , metallurgy , programming language
The temperature dependence of the Raman line width of the ν 1 and ν 2 modes of the SO 4 2−ion in ammonium sulphate was investigated. A sudden change in the full width at half maximum intensity (FWHM) of both bands is observed at the ferroelectric transition point of the crystal. The results are explained in terms of the coupling between phonons originating from these modes and NH 4 + ion pseudo‐spins. The results obtained from pseudospin–phonon coupling formulations agree satisfactorily with the experimental results. The coupling also accounts for the temperature dependence of spontaneous polarization.