Abstract The terahertz spectra of solid-state amino acids with different polarities were measured by terahertz time-domain spectroscopy and Fourier transform infrared spectroscopy. The measured absorption spectra were in good agreement with the results simulated by density functional theory using hybrid functional Becke–3–Lee–Yang–Parr and generalized-gradient approximation Perdew–Burke–Ernzerhof functional with the same basis set of 6-311 G (d, p), respectively. In order to construct a precise crystal structure, dispersion-corrected density functionals were included in the simulation. It was found that Becke–3–Lee–Yang–Parr functional combined with dispersion-correction could produce accurate simulation results that corresponded to the experimental terahertz spectra of solid-state amino acids. However, it greatly increased the time for calculation. The method of Perdew–Burke–Ernzerhof functional with dispersion-correction provided comparable accuracy to Becke–3–Lee–Yang–Parr with dispersion-correction, and much higher simulation speed. The spectral features are assigned as primarily external lattice translations and rotations with lesser contributions to intramolecular torsions.

中文翻译：

---

基于色散校正泛函理论的氨基酸晶体太赫兹光谱

摘要 采用太赫兹时域光谱和傅里叶变换红外光谱对不同极性固态氨基酸的太赫兹光谱进行了测量。测量的吸收光谱与密度泛函理论使用混合泛函 Becke-3-Lee-Yang-Parr 和广义梯度近似 Perdew-Burke-Ernzerhof 泛函模拟的结果非常一致，具有相同的基组 6-311 G（ d, p), 分别。为了构建精确的晶体结构，模拟中包括了色散校正的密度泛函。发现 Becke-3-Lee-Yang-Parr 泛函结合色散校正可以产生与固态氨基酸的实验太赫兹光谱相对应的准确模拟结果。然而，大大增加了计算时间。带有色散校正的 Perdew-Burke-Ernzerhof 泛函方法提供了与带有色散校正的 Becke-3-Lee-Yang-Parr 相当的精度，以及更高的模拟速度。光谱特征主要分配为外部晶格平移和旋转，对分子内扭转的贡献较小。