Time scale of dynamic heterogeneity in model ionic liquids and its relation to static length scale and charge distribution

摘要: We study how dynamic heterogeneity in ionic liquids is affected by the length scale of structural relaxation and charge distribution molecular dynamics simulations performed on two differently charged models liquid their uncharged counterpart. In one model liquid, cation asymmetric, other it symmetric, while neutral counterpart has no with ions. It found that all display heterogeneous dynamics, exhibiting subdiffusive a nonexponential decay relaxation. investigate lifetime heterogeneity, τ(dh), these systems calculating three-time correlation functions to find τ(dh) general power-law behavior respect time, τ(α), i.e., ∝ τ(α)(ζ(dh)). Although asymmetric-charge seemingly more than symmetric-charge model, exponent be similar, ζ(dh) ≈ 1.2, for studied this work. The same scaling relation regardless interactions, or without Coulomb interaction, holds even when long enough become Fickian diffusion. This fact indicates distinctive time from mainly short-range interaction structure.