Abstract
The March-Suhai (MS) partial differential equation for the Dirac density matrix , proved for one- and two-level occupancies, involves both the ground-state density , with its low-order derivatives, and the positive definite kinetic energy density . Here, we examine the relation between the equation of motion for , with input now being the one-body potential of density-functional theory, and the MS equation. The important link is the differential virial theorem, which can be used to remove from the MS differential equation. For multiple occupancy, the Pauli potential enters in an important manner. In one dimension, however, the appearance of the Pauli potential can be avoided, obtaining a necessary condition for to satisfy for arbitrary level occupancy, in the form of a MS-type differential equation.
- Received 9 October 2009
DOI:https://doi.org/10.1103/PhysRevA.81.064503
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