The determination of dissociative adsorption probabilities based on first-principles total-energy calculations requires a numerically efficient and accurate interpolation scheme in order to be able to run a sufficient number of trajectories. Here we present a neural network scheme for the construction of a continuous potential energy surface (PES). We illustrate the accuracy and efficiency of our method for H-2 interacting with the (2 x 2) potassium covered Pd(100) surface. The sticking probability of H-2/K(2 x 2)/Pd(100) is determined by molecular dynamics simulations on the neural network PES and compared to results using an independent analytical interpolation. (C) 2004 Elsevier B.V. All rights reserved.