| Partition Density Functional Theory (PDFT) is a formally exact method to extract molecular information from self-consistent calculations on isolated fragments. We studied the character of PDFT in two different ways. First, by focusing on the cusp displayed by the fragment occupation numbers as a function of the sum of fragment energies; second, by focusing on the character of near-additivity of fragment densities. The results revealed several underlying properties of PDFT, critical to its further development. We also proposed an approximate functional for the partition energy, and demonstrated that it shows promise to circumvent the dissociation problem of Density Functional Theory. Results are illustrated for H2+. |
