Abstract
The formalism of lattice statics is applied to the calculation of the lattice relaxation at a crystal surface. Two alternative methods of solution are demonstrated, one based on lattice Green functions and the other on standard difference equation methods. The techniques are illustrated in calculations for the (100) and (111) surfaces of alpha -Fe, in which a simple bond-breaking model of the surface is employed. The methods described are also applicable to certain types of internal surfaces, and a calculation for a twin boundary in an FCC crystal is outlined.