Brillouin scattering and rotation translation coupling of (KCN)xX1−x mixed crystals

✍ Scribed by C.H. Wang; S. Satija; F. Luty

• Publisher: Elsevier Science
• Year: 1982
• Tongue: English
• Weight: 362 KB
• Volume: 90
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(82)83078-9

✦ Synopsis

Brillouin scattering is used to study the concentration and temperature dependence of longitudinal and transverse phonon frequencies of KCNxBr I-X' KCNxCl l _ x ' and KCNo.8SIo.IS mixed crystals. Unlike pure KCN, mixed crystals with X < 0.7 show no phase transition upon cooling, and the transverse acoustic frequency wTA(llO) displays a minimum at some characteristic temperature T i . Ti is below the phase transition of pure KCN and depends on the Cl-concentration. The Brillouin data are discussed in terms of coupling of the acoustic phonons with orientational motion of CN-ions and mean field theory.