Structure and dynamics of model colloidal clusters with short-range attractions

Abstract

We examine the structure and dynamics of small isolated $N$-particle clusters interacting via short-ranged Morse potentials. "Ideally preprared ensembles" obtained via exact enumeration studies of sticky hard sphere packings serve as reference states allowing us to identify key statistical-geometrical properties and to quantitatively characterize how nonequilibrium ensembles prepared by thermal quenches at different rates $\dot{T}$ differ from their equilibrium counterparts. Studies of equilibrium dynamics show nontrival temperature dependence: nonexponential relaxation indicates both glassy dynamics and differing stabilities of degenerate clusters with different structures. Our results should be useful for extending recent experimental studies of small colloidal clusters to examine both equilibrium relaxation dynamics at fixed $T$ and a variety of nonequilibrium phenomena.