  We present an efficient method to perform overdamped Brownian dynamics
simulations in external force fields and for particle interactions that include
a hardcore part. The method applies to particle motion in one dimension, where
it is possible to update particle positions by repositioning particle clusters
as a whole. These clusters consist of several particles in contact. They form
because particle collisions are treated as completely inelastic rather than
elastic ones. Updating of cluster positions in time steps is carried out by
cluster fragmentation and merging procedures. The presented method is
particularly powerful at high collision rates in densely crowded systems, where
collective movements of particle assemblies is governing the dynamics. As an
application, we simulate the single-file diffusion of sticky hard spheres in a
periodic potential.
