含硫氨基酸的太赫兹光谱

利用太赫兹时域光谱(THz-TDS)技术研究室温条件下多晶含硫氨基酸L-蛋氨酸(Met)和L-半胱氨酸(Cys)的光谱特性, 得到相应的吸收谱和折射率谱, 表明含硫氨基酸在THz波段具有区别于其它氨基酸的显著特征. 在实验测量的有效光谱范围0.2～2.8 THz内, L-蛋氨酸的THz吸收峰分别位于1.06, 1.88和2.70 THz; L-半胱氨酸的吸收峰分别位于1.40, 1.70, 2.33和2.61 THz, 两种氨基酸的平均折射率均为1.44. 利用GAUSSIAN 03软件包中的Hartree-Fock理论计算了蛋氨酸双分子的低频振动谱, 表明了与蛋氨酸各吸收峰对应的分子微观振动模式, 并对实验光谱进行了解析讨论.

Terahertz Time-domain Spectroscopy of Sulfur-containing Amino Acids

The spectral characteristics of polycrystalline sulfur-containing amino acids L-methionine and L-cysteine in a THz range were studied by calculation and terahertz time-domain spectroscopy (THz-TDS) technologies. The absorption spectra and the indexes of refraction were obtained. The experimental results show that the sample has the spectral response in the terahertz spectral range and the terahertz spectra of sulfur-containing amino acids could be used to study the molecular structure and low-frequence collective vibrational modes. The absorption peaks in the frequency range of 0.2～2.8 THz have found at 1.06, 1.88 and 2.70 THz (for methionine), and 1.40, 1.70, 2.33 and 2.61 THz (for cysteine) by THz-TDS, respectively. The average refractive indexes are all 1.44. The vibration absorption spectra of bimolecular L-methionine have been calculated based on HF theory of Gaussian 03. The vibration rotation modes corresponding to the absorption peaks of L-methionine are presented.