Ren Guanhua, Zhou Lu, Chen Ligang, Liu Liyuan, Zhang Jianbing, Zhao Hongwei, Han Jiaguang
Opt Express. 2021 May 10;29(10):14894-14904. doi: 10.1364/OE.419538.
Terahertz spectroscopy provides a powerful and informative link between infrared spectroscopy and microwave spectroscopy, and is now beginning to make its transition from initial development to broader use by chemists, materials scientists and biologists. In this study, utilizing terahertz spectroscopy we monitored the crystallization and isomerization of azobenzene. In flash-frozen trans-azobenzene solutions, the processes of crystallization and phase transition were observed. A new phase has been experimentally confirmed to exist stably at low temperatures. The results on gradual-frozen experiment indicate that the formation of the observed new phase is determined by the cooling rate. Besides, based on the distinctive spectral features of the isomers, the thermal- and photo-induced isomerization processes of azobenzene were investigated. This work presents that the terahertz spectroscopy has a great potential to study the phase transitions and crystallization of liquid samples under different freezing conditions.
太赫兹光谱在红外光谱和微波光谱之间建立了强大且信息丰富的联系，目前正开始从最初的发展阶段过渡到被化学家、材料科学家和生物学家更广泛地应用。在本研究中，我们利用太赫兹光谱监测了偶氮苯的结晶和异构化过程。在快速冷冻的反式偶氮苯溶液中，观察到了结晶和相变过程。实验证实了一种新相在低温下稳定存在。逐步冷冻实验的结果表明，所观察到的新相的形成取决于冷却速率。此外，基于异构体独特的光谱特征，对偶氮苯的热诱导和光诱导异构化过程进行了研究。这项工作表明，太赫兹光谱在研究不同冷冻条件下液体样品的相变和结晶方面具有巨大潜力。
