Total energies of diamond (111) surface reconstructions by a linear combination of atomic orbitals method

An ab initio linear combination of atomic orbitals approach to local-density theory, capable of handling complex structural geometries, is presented. It incorporates a self-consistent treatment of interatomic charge transfer, which allows an accurate calculation of total energies. The method is applied to study a variety of possible 1×1 and reconstructed 2×1 models of the diamond (111) surface. Among the many models suggested, only the Pandey $\pi$-bonded chain model has a lower energy than that of the 1×1 surface. A minimum-energy structure is obtained for this model after extensive consideration of relaxations. No dimerization of the surface chain is found to occur.