(363h) Anomalous Dynamics of Rigid Convex Particle Shapes

The fundamentals of Brownian motion have been largely well understood since the early 20th century, with most recent additions focusing on understanding anomalous diffusion via rescaling of drag coefficients. Such approaches emphasize long-time dynamic behavior, but recent experimental and simulation results have suggested that shape-driven caging at intermediate times can also drastically influence dynamical behavior in anisotropic systems. Here we present the results of a study of the dynamics of a representative family of nearly-hard n-gons. Using molecular dynamics simulations, we study the shape-driven caging behavior that emerges in the mean-square displacement of n-gons at intermediate densities. To rationalize the observed dynamical features, we develop an extended Langevin theory that predicts the observed behavior as well as the translational and rotational relaxation times in the system.