Semiclassical scattering of a particle from a three-dimensional ellipsoid with internal structure is used to model vibration-rotation-translation (VRT) collisional transfer between atoms and diatomic molecules. The result is a very simple analytical expression containing two variable parameters that have a clear physical meaning. Predictions of the model for the Li-2 + Ne system are in reasonably good agreement with experimental results. (c) 2005 Elsevier B.V. All rights reserved.