To simulate the interaction energy between beta-cyclodextrin and linear molecules, a model was constructed from a simple pairwise-additive Lennard-Jones potential combined with a continuum description of the cyclodextrin cavity and the guest molecule. For linear molecules with length L < 6 angstrom, only one pair of potential parameters (sigma, epsilon) were needed to reproduce the main features of the physisorption energy. The variation in the potential energy along the cavity axis was found a well potential where the minimum is deeper as the length or atomic size of the guest molecule increase, in agreement with the results obtained by the all atoms model. (C) 2007 Elsevier B.V. All rights reserved.