Anharmonicity-driven redshift and broadening of sharp terahertz features of α-glycine single crystal from 20 K to 300 K: Theory and experiment
Publication Name
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy
Abstract
For the first time, large single crystals of the simplest amino acid, glycine, have been used to determine the temperature dependence of its terahertz spectrum. High-quality spectra with very sharp absorption features are observed at cryogenic temperatures. The α-glycine structure and the purity of the crystals were verified via Raman spectroscopy and X-ray diffraction. Spectral redshift with increasing temperature was observed for all absorption bands in the terahertz region (10–250 cm , or 1–8 THz) over the temperature range of 20–300 K. X-ray diffraction revealed expansion in all planes of the crystal lattice over the same temperature range. A Bose-Einstein distribution was used to model the frequency position shift of the two lowest-energy fundamental modes at 50 cm and 69 cm . On this basis, we attribute the observed redshift and broadening with increasing temperature to the anharmonic potential associated with the phonon bath. −1 −1 −1
Open Access Status
This publication is not available as open access
Volume
244
Article Number
118635
Funding Number
LE170100020
Funding Sponsor
Australian Research Council