Communication: Relationship between solute localization and diffusion in a dynamically constrained polymer system

We investigate the link between dynamic localization, characterized by the Debye-Waller factor, 〈u(2)〉, and solute self-diffusivity, D, in a polymer system using atomistic molecular dynamics simulations and vapor sorption experiments. We find a linear relationship between lnD and 1/〈u(2)〉 over more than four decades of D, encompassing most of the glass formation regime. The observed linearity is consistent with the Langevin dynamics in a periodically varying potential field and may offer a means to rapidly assess diffusion based on the characterization of dynamic localization.