%A %T Temperature Dependence of Terahertz Spectra of Amino Acid %0 Journal Article %D 2018 %J SPECTROSCOPY AND SPECTRAL ANALYSIS %R 10.3964/j.issn.1000-0593(2018)02-0386-08 %P 386-393 %V 38 %N 02 %U {https://www.gpxygpfx.com/CN/abstract/article_9636.shtml} %8 2018-02-01 %X We employed terahertz time domain spectra (THz-TDS) to measure the spectra of L-Asparagine,L-Cysteine,L-Alanine and L-Tyrosine in the frequency range of 0.5~2 THz at different temperatures. We measured the terahertz absorption spectra of amino acids at room temperature, 250, 200, 150, 100, 70, 40, 10 and 4.5 K by cooling the samples. The absorption peaks of the four amino acids in the low frequency range (0.5~2 THz) were demonstrated by Fourier transform infrared spectroscopy (FTIR) at room temperature, and the range of high frequency band (3~6 THz) was measured by Raman strength of these four amino acids at room temperature using Raman spectroscopy. Measurement results indicated that the temperature variation had an important effect on the absorption spectra. When the temperature falled, the absorption peak shifted to higher frequencies, and several new absorption peaks appeared. Aliphatic and aromatic amino acid displayed different responses in the line width and the absorption strength. Furthermore, we used the quantum chemistry Gaussian 09 software package to calculate the THz spectra of one molecule and unit cell of L-Asparagine and L-Tyrosine at room temperature by density functional theory. The calculation results indicate that intermolecular vibration and rotation strongly influence the absorption in THz frequencies for L-Asparagine and L-Tyrosine.