In-depth investigation on THz spectrum of -butyl-3-methylimidazolium dicyanamide spreading on graphene surface by computational calculation
In-depth investigation on THz spectrum of -butyl-3-methylimidazolium dicyanamide spreading on graphene surface by computational calculation
复制标题
通过计算深入研究在石墨烯表面铺展的-丁基-3-甲基咪唑鎓二氰胺的太赫兹光谱
DOI：
10.1016/j.molliq.2020.113353
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发表时间：
2020
影响因子：
6
通讯作者：
Deng Youquan
中科院分区：
文献类型：
--
作者：
Guan Yongji;Zhang Jiao;Wang Jinyuan;Yang Fulong;Jing Huanwang;Zhang Xiaoping;Deng Youquan
了解特定条件下离子液体（IL）太赫兹光谱的动态变化是一个真正的挑战。本文通过在石墨烯表面铺展1-丁基-3-甲基咪唑鎓二氰胺（[Bmim][DCA]）纳米液滴，通过300 K下的计算计算探测了[Bmim][DCA]太赫兹光谱在30至300 cm−1范围内的动态变化。对计算的太赫兹光谱进行分析可以发现，49.95（阳离子-阴离子）处的振动带随着传播时间从 0 增加到 5 ns，216.45 cm−1（烷基链中 CH3 的摇摆）显示出 16.65 cm−1 蓝移，并且随着传播时间从 10 增加到 20 ns，进一步蓝移 16.65 cm−1，而 266.40 cm−1 处的振动带（甲基中 CH3 的弯曲）仅蓝移16.65 cm−1 随着传播时间从 0 ns 增加到 20 ns。其根本机制是在石墨烯-IL界面上形成更强的吸附层，增强了阳离子和阴离子之间的氢键，并分别限制了烷基链和甲基中CH3基团的扭转和面外弯曲。这里描述的发现代表了通过在石墨烯表面上散布 IL 纳米滴来全面了解 IL 太赫兹光谱动态操纵的重要一步。
Understanding dynamic change of ionic liquid (IL) THz spectrum under certain conditions is a real challenge. Herein, through spreading 1-butyl-3-methylimidazolium dicyanamide ([Bmim][DCA]) nanodroplet on graphene surface, dynamic change of [Bmim][DCA] THz spectrum in the range from 30 to 300 cm−1is probed by computational calculation at 300 K. Analyzing the calculated THz spectra it can be found that vibrational bands at 49.95 (cation-anion bend), 216.45 cm−1(rocking of CH3in alkyl chain) show a 16.65 cm−1blue shift as spreading time increases from 0 to 5 ns and further blue-shift 16.65 cm−1as spreading time increases from 10 to 20 ns, while vibrational band at 266.40 cm−1(bend of CH3in methyl) only blue-shifts 16.65 cm−1as spreading time increases from 0 to 20 ns. The underlying mechanism is revealed to be the stronger adsorbed layer forming on graphene-IL interface which enhances the hydrogen bonds between cations and anions, and constrains the torsion and out-of-plane bend of CH3group in alkyl chain and methyl respectively. The findings described here represent an important step in developing a comprehensive understanding of dynamic manipulation IL THz spectrum by spreading IL nanodroplet on graphene surface.