The dissociative chemisorption of H-2 On Cu(100) has been studied using a six-dimensional wave packet method. All molecular degrees of freedom are treated quantum mechanically, with no dynamical approximations. The potential-energy surface used is an analytical fit to calculations employing density functional theory (DFT), using the generalized gradient approximation (GGA) and a slab representation of the metal surface. The dependence of the reaction probability on normal incidence energy has been obtained for both (v = 0, j = 0) and (v = 1, j = 0) H-2. Comparison to experiment suggests that, on average, the DFT method overestimates the barriers to dissociation by similar to 0.15 eV for H-2 + Cu(100). In broad agreement with experiments on H-2+Cu(lll) and H-2+Cu(110) the calculations show large vibrational inelasticity. A prediction of the survival probability of (v = 1, j = 0) H-2 as a function of incidence energy is also presented. The measurement of this quantity is now feasible and should provide another sensitive test of the DFT potential-energy surface. (C) 1997 American Institute of Physics.