  We study the collision rates and velocities for point-particles of different
sizes in turbulent flows. We construct fits for the collision rates at
specified velocities (effectively a collisional velocity probability
distribution) for particle stopping time ratios up to four; already by that
point the collisional partners are very poorly correlated and so the results
should be robust for even larger stopping time ratios. Significantly, we find
that while particles of very different masses have approximately Maxwellian
collisional statistics, as the mass ratio shrinks the distribution changes
dramatically. At small stopping time ratios, the collisional partners are
highly correlated and we find a population of high number density (clustered),
low relative-velocity particle pairs. Unlike in the case of identical stopping
time collisional partners, this low relative-velocity clustered population is
collisional, but the clustering is barely adequate to trigger bulk effects such
as the streaming instability. We conclude our analysis by constructing a master
fit to the collisional statistics as a function only of the stopping time
ratio. Together with our previous work for identical stopping time particle
pairs, this provides a recipe for including collisional velocity probability
distributions in dust coagulation models for protoplanetary disks. We also
include our recipe for determining particle collisional diagnostics from
numerical simulations.
