▎ 摘　　要

Understanding dynamic change of ionic liquid (IL) THz spectrum under certain conditions is a real challenge. Herein, through spreading 1-butyl-3-methylimidazolium dicyanamide ([aBmim][DCA]) nanodroplet on graphene surface, dynamic change of [Bmim][DCA] THz spectrum in the range from 30 to 300 cm(-1) is 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 an(-1) (rocicing of CH3 in alkyl chain) show a 16.65 cm(-1) blue shift as spreading time increases from 0 to 5 ns and further blue-shift 16.65 cm(-1) as spreading time increases from 10 to 20 ns, while vibrational band at 266.40 cm(-1) (bend of CH3 in methyl) only blue-shifts 16.65 cm(-1) as 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 CH3 group 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. (C) 2020 Elsevier B.V. All rights reserved.