A simple shell model calculation of the differential ionic relaxation of the MgO(100) surface

A model previously reported and applied to the calculation of the differential ionic relaxation of the (100) surfaces of the alkali halides has been extended and applied to MgO(100). In particular, mechanically induced polarisations of the surface ions due to asymmetry in the surface short range forces are now included. The new model is tested by repeating the calculation for selected alkali halides. The results for MgO(100), obtained assuming a fully ionic surface, are consistent with the results of a LEED theory-experiment comparison, and indicate that this surface is not relaxed but may be rumpled on a small scale.