  In this work we study the self-diffusion properties of a liquid of hollow
spherical particles (shells)bearing a smaller solid sphere in their interior
(yolks). We model this system using purely repulsive hard-body interactions
between all (shell and yolk) particles, but assume the presence of a background
ideal solvent such that all the particles execute free Brownian motion between
collisions,characterized by short-time self-diffusion coefficients D0s for the
shells and D0y for the yolks. Using a softened version of these interparticle
potentials we perform Brownian dynamics simulations to determine the mean
squared displacement and intermediate scattering function of the yolk-shell
complex. These results can be understood in terms of a set of effective
Langevin equations for the N interacting shell particles, pre-averaged over the
yolks' degrees of freedom, from which an approximate self-consistent
description of the simulated self-diffusion properties can be derived. Here we
compare the theoretical and simulated results between them, and with the
results for the same system in the absence of yolks. We find that the yolks,
which have no effect on the shell-shell static structure, influence the dynamic
properties in a predictable manner, fully captured by the theory.
