Terahertz spectra of 1-cyanoadamantane in the orientationally ordered and disordered phases

Abstract

AbstractWe report the characteristic terahertz spectra of a plastic crystal and the alterations caused by phase transitions. The low-frequency vibrational modes of 1-cyanoadamantane in orientationally ordered and disordered (plastic) phases were investigated with a terahertz spectrometer. The frequencies of the intramolecular vibrational modes were in good agreement with theoretical calculations. The librational mode, which was directly observed for the first time, appeared at a lower frequency for the plastic phase.Keywords: THz spectroscopyplastic crystalrotator phasephase transitionDFT calculation AcknowledgementsThis study was supported by Kakenhi [23615002], [23655018]; The Foundation for Japanese Chemical Research.