A general purpose analytical expression for collision integrals, up to (l, s) = (4,4), of non-reactive interactions between heavy particles is proposed. The expression has been obtained from the classical cross section calculation for a model potential depending on few parameters, related directly to physical properties of the interacting particles. The fitting function has been verified in the temperature range 10(2) to 10(5) K making these collision integrals suitable for Chapman-Enskog calculations of complex mixtures in high enthalpy fluid dynamics. Parameter values for all the relevant interactions in I I species air model have been reported. (C) 2007 Elsevier B.V. All rights reserved.