Very thin films of Ni, Ta, W, Pb, and Bi in a Ag matrix were irradiated at 77 K with 330 keV Kr ions at doses from 3 to 7×1015ions/cm2and analyzed at room temperature by backscattering of 1.9 MeV He+. The measured mixing efficiencies,Dt/&fgr;FD, for the various tracers correlate with their respective tracer impurity diffusion coefficients and impurity‐vacancy binding energies in Ag. The results concur with previous ones with a Cu matrix and further support the idea that the parameters that are important for thermal diffusion are also important for ion mixing in a thermal spike.