Potential energy surface accuracy is one key issue within the framework of dynamics simulation of gas-surface reactions. Regarding dissociative adsorption of diatomic molecules, the analytical periodic LEPS function hardly reproduces all the intricate structures of the diatom-surface interaction. In this work, we propose an extended version of the standard periodic LEPS including: (i) the implementation of surface-site-dependent Sato parameters, (ii) the addition of Gaussian functions representing entrance channel barriers. This flexible periodic LEPS potential is shown to lead to reliable predictions of the N-2 dissociative adsorption probability on W(100). (C) 2009 Elsevier B.V. All rights reserved.