Condensed Matter Physics, 2011, vol. 14, No. 3, 33602: 1-15
DOI:10.5488/CMP.14.33602           arXiv:1202.4279

Title: Phase behaviour and dynamics in primitive models of molecular ionic liquids
  G.C. Ganzenmüller (Fraunhofer Ernst Mach Institute for High-Speed Dynamics, 4 Eckerstrasse, 79104 Freiburg, Germany),
  P.J. Camp (School of Chemistry, The University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom)

The phase behaviour and dynamics of molecular ionic liquids are studied using primitive models and extensive computer simulations. The models account for size disparity between cation and anion, charge location on the cation, and cation-shape anisotropy, which are all prominent features of important materials such as room-temperature ionic liquids. The vapour-liquid phase diagrams are determined using high-precision Monte Carlo simulations, setting the scene for in-depth studies of ion dynamics in the liquid state. Molecular dynamics simulations are used to explore the structure, single-particle translational and rotational autocorrelation functions, cation orientational autocorrelations, self diffusion, viscosity, and frequency-dependent conductivity. The results reveal some of the molecular-scale mechanisms for charge transport, involving molecular translation, rotation, and association.

Key words: ionic liquids, vapour-liquid transition, dynamics, computer simulation
PACS: 61.20.Ja, 64.70.F-, 66.10.C-, 66.10.Ed, 66.20.-d

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