Mou Sen, Rubano Andrea, Paparo Domenico
Dipartimento di Fisica "Ettore Pancini" , Università di Napoli "Federico II", Complesso Universitario di Monte Sant'Angelo , via Cintia , 80126 Napoli , Italy.
ISASI-Institute of Applied Sciences and Intelligent Systems , Consiglio Nazionale delle Ricerche , via Campi Flegrei 34 , 80078 Pozzuoli , Italy.
J Phys Chem B. 2018 Mar 29;122(12):3133-3140. doi: 10.1021/acs.jpcb.7b10886. Epub 2018 Mar 20.
Ionic liquids are liquid salts at ambient temperature composed of organic cations and organic/inorganic anions. Outstanding physical and chemical properties of ionic liquids lead to increasing application in scientific and industrial field. Ionic liquids have been already investigated by different spectroscopic techniques, including terahertz (THz) time-domain spectroscopy. The usual THz frequency range extends up to 2-3 THz, a relatively narrow band, which can only show the intermolecular vibrational modes. Here, we report about broadband THz spectroscopy of ionic liquids up to 13 THz. Bandwidth of intermolecular absorption band presents an unexpected behavior and strong sharp intramolecular absorptions are shown. In addition, we found violation of the approximation of harmonic oscillator used to predict the peak shift of intermolecular absorption band.
离子液体是在环境温度下由有机阳离子和有机/无机阴离子组成的液体盐。离子液体出色的物理和化学性质使其在科学和工业领域的应用日益增加。人们已经通过不同的光谱技术对离子液体进行了研究，包括太赫兹（THz）时域光谱。通常的太赫兹频率范围延伸至2 - 3太赫兹，这是一个相对较窄的波段，只能显示分子间振动模式。在此，我们报告了高达13太赫兹的离子液体宽带太赫兹光谱。分子间吸收带的带宽呈现出意想不到的行为，并且显示出强烈尖锐的分子内吸收。此外，我们发现用于预测分子间吸收带峰值位移的简谐振子近似存在偏差。
