Raman intensities near second‐order transitions. Part II‐tris‐(sarcosine)calcium chloride

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.