Quasiharmonic versus exact surface free energies of Al: A systematic studyemploying a classical interatomic potential

We discuss a computationally efficient classical many-body potential design ed to model the Al-Al interaction in a wide range of bonding geometries. We show that the potential yields results in excellent agreement with experim ent and ab initio calculations for a number of bulk and surface properties, among others for surface and step formation energies, and self-diffusion b arriers. As an application, free-energy calculations are performed for the Al (100) surface by Monte Carlo thermodynamic integration and the quasiharm onic approximation. Comparison of the latter approximation with the referen ce Monte Carlo results provides information on its range of applicability t o surface problems at high temperatures. [S0163-1829(99)03831-X].