On the structure and dynamics of ionic liquids

Mario Del Popolo, G.A. Voth

Research output: Contribution to journalArticlepeer-review

562 Citations (Scopus)

Abstract

The structure and dynamics of the ionic liquid 1-ethyl-3-methylimidazolium nitrate is studied by molecular dynamics simulations. We find long-range spatial correlations between the ions and a three-dimensional local structure that reflects the asymmetry of the cations. The main contribution to the configurational energy comes from the electrostatic interactions which leads to charge-ordering effects. Radial screening and threedimensional distribution of charge are also analyzed. The motion of a single ion is studied via velocity and reorientational correlation functions. It is found that ions "rattle" in a long-lived cage, while the orientational structure relaxes on a time scale longer than 200 ps. As in a supercooled liquid, the mean square displacements reveal a subdiffusive dynamics. In addition, the presence of dynamic heterogeneities can be detected by analyzing the non-Gaussian behavior of the van Hove correlation function and the spatial arrangement of the most mobile ions. The short-time collective dynamics is also studied through the electric current time correlation function.
Original languageEnglish
Pages (from-to)1744-1752
Number of pages9
JournalJournal of Physical Chemistry B
Volume108(5)
Issue number5
DOIs
Publication statusPublished - 05 Feb 2004

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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