Energy functionals in momentum space: Exchange energy, quantum corrections, and the Kohn-Sham scheme

We derive, to leading order, the momentum-space functionals of the exchange energy and of the quantum corrections to the electrostatic energy. The energy functionals thus refined are used to introduce a Kohn-Sham scheme for self-consistent momentum-space calculations. This scheme is applied to helium and beryllium. The results differ from those obtained in the standard Kohn-Sham scheme in configuration space. The total binding energies predicted by the momentum-space computation are somewhat better than those of the configuration-space method