Towards an exact orbital-free single-particle kinetic energy density for the inhomogeneous electron liquid in the Be atom

Alisa Krishtal, Norman March, Christian Van Alsenoy

Holas and March (Phys. Rev. A51, 2040 (1995)) wrote the gradient of the one-body potential V(r) in terms of low-order derivatives of the idempotent Dirac density matrix built from…