Fractional variant of Stokes-Einstein relation in aqueous ionic solutions under external static electric fields

Both ionic solutions under an external applied static electric field E and glassy-forming liquids under undercooled state are in non-equilibrium state. In this work, molecular dynamics (MD) simulations with three aqueous alkali ion chloride (NaCl, KCl, and RbCl) ionic solutions are performed to exploit whether the glass-forming liquid analogous fractional variant of the Stokes-Einstein relation also exists in ionic solutions under E. Our results indicate that the diffusion constant decouples from the structural relaxation time under E, and a fractional variant of the Stokes-Einstein relation is observed as well as a crossover analogous to the glass-forming liquids under cooling. The fractional variant of the Stokes-Einstein relation is attributed to the E introduced deviations from Gaussian and the nonlinear effect.