Spatially resolved fast dynamics reveal the aggregation mechanism in two-dimensions.

Abstract

Two typical morphologies of two-dimensional aggregates are considered: compact crystalline clusters and string-like non-compact conformations. Simulated trajectories of both types of aggregates are analysed with fine spatial resolution. While the long-time geometry of such trajectories appears to be statistically identical for the two conformations, the self-overlap statistics reveal two distinct short-time pre-caging mechanisms. While the length-scale is directly proportional to the time-scale for particles in compact aggregates, a non-monotonic relationship holds for non-compact clusters. The relationship between short length-scale and fast time-scale for particle localization might hold the key to the structure-function relationship of aggregate forming systems and other non-equilibrium soft materials.