Micro-Raman investigations of pressure-induced transformations in MBBA

✍ Scribed by J. F. Meng; G. P. Sinha; P. S. Dobal; R. S. Katiyar

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 180 KB
• Volume: 30
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/(sici)1097-4555(199903)30:3<217::aid-jrs362>3.0.co;2-5

✦ Synopsis

The pressure-induced changes in the Raman spectra of a nematic N-(p-methoxybenzylidene)-p-(n-butyl)aniline (MBBA) liquid crystal were investigated in the wavenumber range 5-1670 cm-1. With increasing pressure, the Raman spectrum undergoes qualitative changes in a systematic manner and three distinct phase transitions, from nematic to plastic crystal, from plastic to crystalline and from to are obtained around 0.39, 0.78 and C 6P C 6P C 5P , 3.12 GPa, respectively. The room temperature results obtained in this pressure study provide information on the structural modiÐcations and phase behavior of MBBA molecules. The appearance of a plastic-like state was veri-Ðed just below the nematic phase. The e †ects of pressure variation on MBBA phonon modes are discussed in detail.