Electron Correlations in Kohn–Sham Exchange‐Only Theory
We provide an interpretation for the “exchange” energy and potential of Kohn–Sham exchange‐only theory, or equivalently that of the optimized potential method (OPM), which shows that in addition to contribution due to the Pauli exclusion principle, there is a kinetic component to these properties. The interpretation is in terms of a conservative field ROPM(r), which is a sum of two fields, one representative of Pauli electron correlations and the other of kinetic effects. The OPM exchange potential is derived via the differential virial theorem to be the work done to move an electron in the field ROPM(r). The OPM exchange energy is then expressed via the integral virial theorem in terms of this field. A similar interpretation for the energy and potential may also be derived directly from the OPM integral equation.
Sahni, V., & Slamet, M. (1999). Electron correlations in Kohn–Sham exchange‐only theory. International Journal of Quantum Chemistry, 71(6), 473-480. Doi: 10.1002/(SICI)1097-461X(1999)71:63.0.CO;2-V