Helium diffraction data from the nickel (110) surface has indicated a very small corrugation which decreases with increasing incident energy of He atoms while for copper a larger corrugation effect is observed. None of the theoretical calculations based on surface electronic charge density reported to date have been successful in reproducing the value or the trend for Ni(110). It is suggested that the differences between Ni and Cu are due to the unfilled d shell of Ni. Configuration interaction calculations on He-NiI4and He-Cu14, using an embedding theory, have been performed for low lying electronic states to determine interaction potentials and softness parameters. For Ni the interaction potentials are found to be similar for atop atom and midbond He trajectories, while for Cu, the atop atom site is much more repulsive in accord with the He diffraction data. © 1984, American Vacuum Society. All rights reserved.