Exchange Cross Sections for Hard Binaries
  We present results on the exchange cross section for the interaction between a hard binary and a field of single stars, for arbitrary masses. The results are based partly on extensive numerical scattering experiments, and partly on analytic estimates of the mass-dependence of the cross section. They can be used to estimate the rate of exchange in an arbitrary mixture of masses, provided that the binary is hard. 
Douglas C. Heggie, Piet Hut and Steven L.W. McMillan