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High-quality, temperature-dependent terahertz spectroscopy of single crystalline L-alanine: Experiment and density-functional theory.
- Source :
-
Journal of Chemical Physics . 6/28/2021, Vol. 154 Issue 24, p1-13. 13p. - Publication Year :
- 2021
-
Abstract
- For the first time, the terahertz transmittance spectra of l-alanine have been measured using a single crystal. Measurements were obtained over a large temperature range (12–300 K) and revealed 18 absorptions between 20 and 250 cm−1. These modes were sharp and symmetric, a feature of single crystals and low temperatures. The spectra were directly compared to those of a powdered pellet sample. Raman spectroscopy and x-ray diffraction were used to confirm the sample's structure and purity. With increasing temperature, all modes exhibit spectral redshift, well described by a Bose–Einstein model, indicating the phonon origin of the absorptions. The exceptions are the 91 and 128 cm−1 modes. The former blueshifts. The latter initially blueshifts but transitions to redshifting. Both behaviors are anomalous. Density-functional theory modeling helped assign all the observed modes. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00219606
- Volume :
- 154
- Issue :
- 24
- Database :
- Academic Search Index
- Journal :
- Journal of Chemical Physics
- Publication Type :
- Academic Journal
- Accession number :
- 151175605
- Full Text :
- https://doi.org/10.1063/5.0054063