We present results of extensive density functional theory (DFT) calculations for H and H-2 interacting with NiAl(110). Continuous representations of the full dimensional potential energy surface (PES) for the H/NiAl(110) and H-2/NiAl(110) systems are obtained by interpolation of the DFT results using the corrugation reducing procedure. We find a minimum activation energy barrier of similar to300 meV for dissociative adsorption of H-2, which is consistent with the energy threshold obtained in molecular beam experiments for H-2 (nu=0). We explain vibrational enhancement observed in experiments as the consequence of vibrational softening in the entrance channel over the most reactive surface site. The H-2/NiAl(110) PES shows a high surface site selectivity: for energies up to 0.1 eV above threshold, H-2 adsorption can only take place around top-Ni sites (within a circle of radius similar to0.3 Angstrom). A strong energetic corrugation is observed: energy barriers for dissociation vary by more than 1 eV between the most and the least reactive sites. In contrast, geometric corrugation is much less pronounced and comparable to that of low index single metal surfaces like Cu or Pt. (C) 2004 American Institute of Physics.