Challenge of creating accurate and effective kinetic-energy functionals

The accuracy and effectiveness of various kinetic-energy functionals in providing total noninteracting kinetic energies, atomization kinetic energies, and equilibrium properties is evaluated. Employing converged Kohn-Sham densities, we assess various kinetic-energy functionals in a non-self-consistent manner. It is found that the gradient expansion, the Pearson-Gordon local truncation scheme, and the [4/3]-Padé approximant of DePristo and Kress provide reliable estimates for the total noninteracting kinetic energy. The estimates for the atomization kinetic energy and equilibrium geometries are, however, far from being reliable for chemical applications