Ordering and single-file diffusion in colloidal systems.

ABSTRACT

The structural properties and the single-file diffusion in one-dimensional interacting colloidal systems are studied by means of Brownian dynamics simulations. We consider three types of particle interactions, namely, Weeks-Chandler-Andersen, screened Coulomb, and superparamagnetic potentials. We find that, regardless of the interaction potential, at low densities particles are distributed in a typical fluidlike structure and at higher densities or potential strengths become spatially correlated at long-distances. Particularly, our findings demonstrate that one-dimensional systems, with particles interacting repulsively, show common structural and dynamical behaviors at the boundary in which the degree of ordering changes dramatically; the main peak of the static structure factor becomes highly narrow with a height of S(c)≈7, whereas the reduced mobility factor F, which is associated with the single-file diffusion at long-times or long wavelengths, reaches values F(∗)≈0.1. These features are analyzed and discussed in the context of a local order-disorder transition.