Premium
Raman intensities near second‐order transitions. Part II‐tris‐(sarcosine)calcium chloride
Author(s) -
Chen Ting,
Scott J. F.
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.1250211110
Subject(s) - sarcosine , ferroelectricity , chemistry , curie temperature , raman spectroscopy , phase transition , raman scattering , soft modes , analytical chemistry (journal) , polar , intensity (physics) , nuclear magnetic resonance , condensed matter physics , optics , physics , quantum mechanics , chromatography , glycine , ferromagnetism , dielectric , amino acid , biochemistry
The theory of light‐scattering intensities originally discussed by Fleury and developed recently by the present authors for LaP 5 O 14 was applied to the second‐order ferroelectric phase transition in tris(sarcosine)calcium chloride, (CH 3 NHCH 2 COOH) 3 CaCl 2 · It was found that the combination of critical exponents 2β‐γ′ = +0.05 ± 0.002; this is in good agreement with mean field theory, which predicts exactly zero, and sets strict limits on the intensity (small) of any dynamic central mode near the Curie temperature T c . T o ′, the transition temperature extrapolated from soft‐mode frequency squared vs. temperature, was found to be 131.5 ± 0.1 K, about 1 K above T c , demonstrating weak acousto‐optic coupling.