title: Origin of heterogeneous dynamics in local molecular structures of ionic liquids.
abstract: Room-temperature ionic liquids (ILs) are generally considered as structurally heterogeneous with inherent polar/apolar phase separation. However, even after a decade of research, local dynamics in the heterogeneous structures of ILs remain neglected. Such local dynamics may influence the ion transport of electrolytes, as well as the reaction rate of solvents. In this study, we performed molecular dynamics simulation to analyze the local dynamics for the structural heterogeneity of ILs. Calculations of the diffusion, reorientation, and association dynamics showed a distinct heterogeneous dynamics between the polar and apolar regions of ILs. Further studies demonstrated that such local dynamic differences originate from local structural heterogeneity. Different energy barriers determine a predominant fast reorientation dynamics in apolar regions and a locally vibrating behavior in polar regions. Additionally, we suggested a new jumping mechanism to clarify the dynamic heterogeneity of ions in the polar regions. The results will help determine the origin of the heterogeneous dynamics in IL local structures and provide a theoretical basis for tuning the dynamic properties of ILs used as electrolytes or reaction solvents.
authors.affiliation: Department of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China. franksha@aliyun.com.
authors.forename: Maolin
authors.initials: M
authors.lastname: Sha
authors.affiliation: Department of Chemistry and Chemical Engineering, Xuzhou Institute of Technology, Xuzhou 221018, China.
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China. franksha@aliyun.com.
authors.forename: Huaze
authors.initials: H
authors.lastname: Dong
authors.affiliation: Department of Chemistry and Chemical Engineering, Hefei Normal University, Hefei 230061, China. franksha@aliyun.com.
authors.forename: Fabao
authors.initials: F
authors.lastname: Luo
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P. B. Box 800-204, Shanghai 201800, China. wuguozhong@sinap.ac.cn.
authors.forename: Fangling
authors.initials: F
authors.lastname: Jiang
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P. B. Box 800-204, Shanghai 201800, China. wuguozhong@sinap.ac.cn.
authors.forename: Zhongfeng
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Institute of Atomic and Molecular Physics, Anhui Normal University, Wuhu 241000, China.
authors.forename: Guanglai
authors.initials: G
authors.lastname: Zhu
authors.affiliation: Shanghai Institute of Applied Physics, Chinese Academy of Sciences, P. B. Box 800-204, Shanghai 201800, China. wuguozhong@sinap.ac.cn.
authors.forename: Guozhong
authors.initials: G
authors.lastname: Wu