Temperature Dependence in the Terahertz Spectrum of Nicotinamide: Anharmonicity and Hydrogen-Bonded Network.
We have investigated the terahertz-spectral property of nicotinamide focusing on the temperature dependence in the range of 14-300 K. We observed that almost all peaks in the terahertz spectrum of the nicotinamide crystal showed a remarkable shift with temperature, whereas the lowest-frequency peak at 34.8 cm-1showed a negligible shift with temperature. By analyzing the terahertz spectrum with the dispersion-corrected density functional theory calculations, we found that the difference in the temperature dependence of the peak shift is well understood in terms of the presence/absence of stretching vibration of the intermolecular hydrogen bond in the mode and the change of cell parameters. The anharmonicity in the dissociation potential energy of very weak intermolecular hydrogen bonding causes the remarkable peak shift with temperature in the terahertz spectrum of nicotinamide. This finding suggests that the assignment and identification of peaks in the terahertz spectrum are systematically enabled by temperature-dependent measurements.
Graduate School of Agricultural Science, Tohoku University , Sendai 980-0845, Japan.|RIKEN Advanced Science Institute , Sendai 980-0845, Japan.
Masae
http://orcid.org/0000-0001-7717-6512
M
Takahashi
Graduate School of Agricultural Science, Tohoku University , Sendai 980-0845, Japan.|RIKEN Advanced Science Institute , Sendai 980-0845, Japan.
Nubuyuki
N
Okamura
Graduate School of Agricultural Science, Tohoku University , Sendai 980-0845, Japan.
Xinyi
X
Fan
Graduate School of Agricultural Science, Tohoku University , Sendai 980-0845, Japan.
Hitoshi
H
Shirakawa
RIKEN Advanced Science Institute , Sendai 980-0845, Japan.
Hiroaki
H
Minamide