ORBITAL-FREE KINETIC-ENERGY FUNCTIONALS FOR 1ST-PRINCIPLES MOLECULAR-DYNAMICS

We study a class of kinetic-energy functionals suitable for orbital-free first-principles molecular dynamics and assess their validity for the study of simple metals. With a simple functional which guarantees correct behavior to second order in perturbation theory and approximates higher-order terms, we find that for Na accuracy is already achieved, while Al is reasonably well described. The simple functional can be readily generalized to include higher-order terms.