Density-Matrix-Power Functional: Performance for Finite Systems and the Homogeneous Electron Gas

An exchange correlation energy functional involving fractional power of the one-body reduced density matrix [Phys. Rev. B {\bf 78}, 201103 (2008)] is applied to finite systems and to the homogeneous electron gas. The performance of the functional is assessed for the correlation and atomization energies of the molecules contained in the G2 set and for the correlation energy of the homogeneous electron gas. High accuracy is found for these two very different types of systems.