Calculation of the Halfwidth and the Activation Energy for the Soft Raman Modes in the Brominated Compounds of Tris-Sarcosine Calcium Chloride

Abstract

This letter contributes how to calculate the anomalous behavior for the damping constant (halfwidth) of the ferroelectric Tris-Sarcosine Calcium Chloride (TSSC) and its brominated compounds TSSC1−xBrx (x = 0.13, 0.42 and 0.60) from the wavenumber data of the soft modes below the phase transition temperature of TC. The pseudospin-phonon coupled (PS) and the energy fluctuation (EF) models derived from the dynamical Ising model were used. Both PS and EF models have been used to contribute understanding the temperature dependence of the phase transition mechanism of TSSC1−xBrx. In addition, values of the activation energy for TSSC1−xBrx (x = 0, 0.13, 0.42 and 0.60) were extracted from the damping constant as calculated from both models (PS and EF). Our results indicate order-disorder type phase transition for TSSC1−xBrx.
 HIGHLIGHTS
 
 This work contributes how to calculating the critical behavior of the halfwidth for the soft Raman modes in ferroelectric TSSC1-xBrx (x = 0, 0.13, 0.42 and 0.60) liquid crystals from their observed wavenumbers data. Also, the values of the activation energy close to the ferroelectric-paraelectric phase transition of these crystals was deduced.
 This calculation of the halfwidth and the activation energy were performed using the pseudospin-phonon coupled (PS) and the energy fluctuation (EF) models in the ferroelectric phases (T < TC) of the crystals studied here.
 
 GRAPHICAL ABSTRACT