苯丙氨酸的太赫兹光谱测试与理论研究

Experimental and Theoretical Study of Phenylalanine in THz Range

采用太赫兹时域光谱（THz-TDS）技术,在室温氮气环境下对固态苯丙氨酸进行了光谱测试,获得了样品在THz波段的特征吸收谱,发现苯丙氨酸样品在有效光谱范围（0.2～2.2 THz）内有两个明显的特征吸收峰,分别位于1.23和1.99THz处.用从头算理论,在HF/6-31G水平下对苯丙氨酸分子进行结构优化和频率计算,得到了样品在0.1～10 THz的振动频谱.在有效光谱范围内,理论计算结果与实验相互对应且符合较好,同时根据计算结果对实验中特征吸收的振动模式进行了指认.

This paper reports the experimental and theoretical absorption spectra of phenylalanine in the far-infrared frequency range. The absorption spectrum of phenylalanine has been measured by terahertz time-domain spectroscopy（THz-TDS） in THz range at room temperature. Ab initio theory method at HF/6-31G level is used to optimize the geometric structure of phenylalanine. The equilibrious geometry of phenylalanine is obtained and the vibration frequencies of the phenylalanine have been calculated between 0.1 and 10 THz at the same theory level. The theoretical results simulated by Gaussian 03 in THz range show significantly agreement with the experimental results. This study can not only assign the characteristic absorption of the sample, but also can provde the absorption frequencies in wider effective spectra range.