Partition density-functional theory

Partition density functional theory is a formally exact procedure for calculating molecular properties from Kohn-Sham calculations on isolated fragments, interacting via a global partition potential that is a functional of the fragment densities. An example is given and consequences discussed.

Figure 1

Solid line: The exact spin-unpolarized ground state of 12 electrons in the potential of Eq. (15). Dashed lines: The fractionally occupied fragment densities. By symmetry, the other half of the density is simply the mirror image of that shown.

Figure 2

The exact partition potential (solid line) for the atomized chain and the fragment potential for the last atom (dashed line). The ground state with an occupation of $0.77$ in this potential can be seen as the end fragment density in Fig. 1.

Figure 3

The convergence of the fragment occupation values, $N_{\alpha }$, during an exact PDFT calculation.