FURTHER ORBITAL-FREE KINETIC-ENERGY FUNCTIONALS FOR AB-INITIO MOLECULAR-DYNAMICS

A recently introduced scheme for ab initio molecular-dynamics with an orbital-free density functional [Phys. Rev. B 49, 5220 (1994)] is exte nded so that the kinetic-energy functional guarantees correct results at third order of perturbation theory. The new density functional give s improved accuracy, yielding good agreement with well-converged Kohn- Sham results for many properties of metals such as aluminum. This mole cular-dynamics scheme retains many of the advantages of the old: it is very fast, exhibits close to linear scaling with system size, and may be readily ''conditioned'' to maximize the molecular-dynamics time st ep.