To simulate the interaction energy between beta-cyclodextrin and linear molecules, we elaborate a model based on a simple pairwise-additive Lennard-Jones potential and a continuum description of the cyclodextrin cavity and the guest molecule. For linear molecules with length L >= 6 angstrom, two pairs of potential parameters (sigma(1),epsilon(1); sigma(2),epsilon(2)) are needed to reproduce the main features of the physisorption energy obtained by the all atoms model. The penetration potential presents two minima inside the cavity, separated by a potential barrier associated with a rotation of the linear molecule of about 180 with respect to the cavity axis. (C) 2007 Elsevier B.V. All rights reserved.