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目的:获得齐多夫定和司他夫定在太赫兹(THz)波段的特征响应,得到其低频振动光谱,并从理论上分析光谱产生的原因。方法:室温下,利用太赫兹时域光谱(THz-TDS)技术测量得到2种药物的频谱响应,再运用密度泛函理论的B3LYP方法结合基组6-31G(d,p)分别对2种药物进行单分子结构和晶体结构的模拟计算,分析实验和模拟结果,并对吸收峰处的振动模式进行归属。结果:实验表明,这2种药物在THz波段都存在特征吸收峰,且两者的吸收谱有差异明显;单分子结构的模拟计算预测出了2种药物在0.2~1.8 THz范围内的部分实验特征峰,而晶体结构的模拟计算成功预测出了所有的实验特征峰,明显优于单分子模拟。结论:利用THz光谱分析可以有效地对夫定类药物进行鉴别;利用晶体密度泛函理论模拟可以较为准确地对物质在THz波段的吸收峰进行指认和振动归属。
OBJECTIVE: To obtain the characteristic response of zidovudine and stavudine in the terahertz (THz) band, obtain the low-frequency vibrational spectrum and analyze the reason of the spectrum theoretically. Methods: The spectral response of two drugs was measured by THz-TDS technique at room temperature. The density functional theory (B3LYP) method was used in combination with 6-31G (d, p) Drugs are used to simulate single molecule structure and crystal structure, analyze experiment and simulation results, and assign vibration modes at absorption peak. Results: The experimental results showed that both of the two drugs showed characteristic absorption peaks in the THz band, and the absorption spectra of the two drugs showed obvious differences. The simulation calculation of the single molecule structure predicted some experiments of the two drugs in the range of 0.2-1.8 THz Characteristic peaks, and the crystal structure of the simulation calculation successfully predicted all the experimental characteristic peaks, significantly better than the single-molecule simulation. Conclusion: THz spectral analysis can be used to identify the drugs of the same class. The density functional theory (DFT) simulation can be used to identify and vibrate the absorption peaks of THz band more accurately.