TIGHT-BINDING INTERATOMIC POTENTIALS BASED ON TOTAL-ENERGY CALCULATION - APPLICATION TO NOBLE-METALS USING MOLECULAR-DYNAMICS SIMULATION

We present an alternate approach to parametrizing the expression for t he total energy of solids within the second-moment approximation (SMA) of the tight-binding theory. In order to obtain the necessary paramet ers, we do not use the experimental values of the lattice constant, th e elastic constants, and the cohesive energy, but we fit to the total energy obtained from first-principles augmented-plane-wave calculation s as a function of volume. In addition, we shift the total-energy grap hs uniformly so that at the minimum they give the experimental value o f the cohesive energy. We have applied the above methodology to perfor m molecular-dynamics simulations of the noble metals. For Cu and Ag ou r results for vacancy formation energies, relaxed surface energies, ph onon spectra, and various temperature-dependent quantities are of comp arable accuracy to those found by the standard SMA, which is based on fitting to several measured data. However, our approach does not seem to work as well for Au.