  We present a simple method to calculate the binary collision rate between
atoms in near-resonant optical lattices. The method is based on the Monte Carlo
wave function simulations and the collision rate is obtained by monitoring the
quantum flux beyond the average distance between the atoms. To illustrate the
usefulness of the method, we calculate the collision rates for a wide range of
occupation densities and various modulation depths of the lattice. The method
presented here combined with the semiclassical calculations accounting for
intra-well collisions can simplify the study of the effects of binary
collisions on the dynamics of atomic clouds trapped in near-resonant optical
lattices.
