Evidence for mesoscopic local structures in ionic liquids: CARS signal spatial distribution of Cnmim[PF6] (n = 4, 6, 8)

We report the measurements of CARS signal spatial distribution of three room-temperature ionic liquids, Cnmim[PF6] (n = 4, 6, 8). The result suggests that specific local structures with a mesoscopic size are formed and that the dimension of these local structures increases with increasing the alkyl-chain length n.