Perturbative expressions are presented for calculating the adiabatic potential curves between metastable He(2 S-3, 2 S-1) helium atoms and the rare gas atoms Ne, Ar, Kr and Xe. The first-order terms are obtained by assuming that the main contribution comes from the 2s-wave electron of the metastable helium atom and the s-wave electrons in the outermost shell of the rare gas atom. With the second-order van der Waals terms modified with Tang-Toennies damping functions, a simple analytical expression is obtained for the entire potential curves. The van der Waals well depths and positions are in good agreement with the experiments. (C) 2002 Elsevier Science B.V. All rights reserved.