Open AccessTerahertz study of L-asparagine and its monohydrate
Author(s) -
Yang Jq,
SX Li,
H. W. Zhao,
Zhang Jb,
Na Yang,
DD Jing,
Wang Cy,
Jianming Han
Publication year - 2014
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.63.133203
Subject(s) - terahertz radiation , intermolecular force , materials science , terahertz time domain spectroscopy , terahertz spectroscopy and technology , spectroscopy , infrared spectroscopy , fourier transform infrared spectroscopy , molecular vibration , differential scanning calorimetry , analytical chemistry (journal) , infrared , asparagine , optics , molecule , physics , optoelectronics , nuclear magnetic resonance , chemistry , raman spectroscopy , organic chemistry , thermodynamics , quantum mechanics , enzyme
Low-frequency collective vibrational modes of biomolecules which often lie in terahertz (THz) band, make the terahertz time-domain spectroscopy (THz-TDS) an important technique for molecular identification and medicine quality inspection. Distinctive THz spectra between L-asparagine and its monohydrate were observed and the dehydration process of L-asparagine monohydrate was tracked by THz-TDS. Experiments indicate that THz wave is sensitive to phase transitions in crystals, dehydration process, and weak molecular interactions. Multi-techniques including differential scanning calorimetry and thermogravimetry, Fourier transform infrared spectroscopy, and powder X-ray diffraction are performed to investigate the thermodynamic properties, intermolecular and intramolecular vibrations, and molecular packing patterns of L-asparagine and its monohydrate. These measurements support the reliability of THz spectroscopy. To simulate and analyse the vibration modes of L-asparagine monohydrate, density functional theory calculations are performed using a Perdew Burke and Ernzerhof generalized gradient approach; the results agree well with the experimental observations.