Hybridized kinetic energy functional for orbital-free density functional method

We propose a hybridized kinetic energy functional, aT(TF) + bT(vW), where T-TF is the Thomas-Fermi functional and T-vW the von Weizsacker functional while a and b are adjustable parameters. The new functional is implemented in orbital-free plane-wave density functional method. in which a conjugate-gradient line-search scheme of electronic minimization is incorporated. Calculations with the fitted a and b show that this kinetic energy functional can describe the structures of small Si, Al and Si-Al alloy clusters with reasonable accuracy. (C) 2008 Published by Elsevier B.V.