A functional of the one-body-reduced density matrix derivedfrom the homogeneous electron gas:Performance for finite systems

摘要

An approximation for the exchange-correlation energy of reduced-density-matrix-functional theorywas recently derived from a study of the homogeneous electron gas N. N. Lathiotakis, N. Helbig,and E. K. U. Gross, Phys. Rev. B 75, 195120 (2007). In the present work, we show how thisapproximation can be extended appropriately to finite systems, where the Wigner Seitz radius rs, theparameter characterizing the constant density of the electron gas, needs to be replaced. We apply thefunctional to a variety of molecules at their equilibrium geometry and also discuss its performanceat the dissociation limit. We demonstrate that, although originally derived from the uniform gas, theapproximation performs remarkably well for finite systems.