A method has been developed to describe the force field of atomic species interacting with hydrocarbon molecules, either aliphatic or aromatic, of use for molecular dynamics simulations. The potential energy surfaces are represented by a simple analytical form written as a sum of atom-bond interaction contributions, for which a new potential model, [n(x),m], is proposed. The prototypical systems, methane and benzene, interacting with rare gases He, Ne, Ar, Kr and Xe, are analyzed as test cases. The method appears suitable for extensions to more complex systems, including modifications for treating ion-ion and ion-molecule interactions. (C) 2004 Elsevier B.V. All rights reserved.