Experimental Studies of Phase Transitions

本研究项目将利用布里渊散射和拉曼散射来研究几种介质晶体中的非公度相变和锁定相变。具体项目包括：1)研究特性温度TI附近亚硒酸钾的纵向声学异常以及亚硒酸钾和四甲基四氯锌酸钾中有争议的横向声学模式的不对称性；2)用布里渊散射消除关于硫脲介电异常的争议；3)研究氯化锂溶液和其他玻璃形成材料的玻璃化转变；4)新研究熔点附近晶体的表面声学模式，以寻找表面熔化的开始。

This research project will make use of Brillouin and Raman scattering to investigate the incommensurate and lock-in phase transitions in several dielectric crystals. The specific projects include: 1) studies of the longitudinal acoustic anomalies in potassium selenate near the characteristic temperature TI and controversial asymmetries in transverse acoustic modes in potassium selenate and tetramethyltetrachlorozincate; 2) clearing up the remaining controversy concerning the dielectric anomaly in thiourea with Brillouin scattering; 3) studies of the glass transition with lithium chloride solutions and other glass-forming materials; 4) a new study of surface acoustic modes of crystals near the melting point in order to search for the onset of surface melting.