Before revision:  We apply the method to simulate interactions of an m-valent ligand with an n-valent cell-surface receptor . Simulation results show that  the rejection-free method is more efficient over wide parameter ranges than a related method that relies on rejection sampling .
After revision:  We apply the method to simulate interactions of an m-valent ligand with an n-valent cell-surface receptor . Simulation results show that the rejection-free method is more efficient over wide parameter ranges , and the rejection-free method is more efficient for simulating systems in which aggregation is extensive. The rejection-free method reported here should be useful for simulating a variety of systems in which multisite molecular interactions yield large molecular aggregates .