利用太赫兹时域光谱技术(THz-TDS)技术, 对L-, D-, DL-α-丙氨酸晶体粉末进行了太赫兹光谱的室温测量。 在0.3～3.0 THz范围内, 观察到数个吸收峰, 发现其两种旋光体(L-, D-丙氨酸)与其外消旋化合物(DL-丙氨酸)在吸收峰上有较大差异。 同时, 运用基于密度泛函理论(DFT)的第一性原理计算, 对丙氨酸的3种样品进行了振动光谱的理论模拟, 得到了与实验数据较为吻合的结果, 指出THz波段的吸收光谱是来源于通过氢键作用产生的分子集体振动。

In the present paper the terahertz time-domain spectroscopy (THz-TDS) was used to measure the absorption spectra of L-, D-, DL-α-alanine at room temperature. A number of well-resolved absorption peaks were observed in the range of frequencies from 0.3 to 3.1 THz, which showed large differences in the spectra between the enantiomers(L-, D-alanine) and the racemic compound(DL-alanine). In parallel with the experimental study, the computed vibrational spectra were also obtained by using first principles calculations based on the density functional theory(DFT), which were in good agreement with the experimental data. Results show that the absorption spectra in terahertz region originate from the collective vibration based on hydrogen bonds.