A stochastic approach to colloidal particle collision/agglomeration
  Colloidal particles that experience perfectly elastic collisions can be modelled using Langevin processes with specular reflection conditions. The article presents a discretisation scheme and offers a conjecture for the rate of convergence of the bias produced. Numerically, these conjectures are confirmed for the specular reflection scheme but also for the absorption scheme, which models perfect agglomeration. 
Mireille Bossy, Radu Maftei, Jean-Pierre Minier, Christophe Profeta
cond-mat.stat-mech math.NA