Boosting the OEP2-sc method with spin-component scaling
The semi-canonical second-order optimised effective potential (OEP2-sc) method [R.J. Bartlett, I. Grabowski, S. Hirata and S. Ivanov, J. Chem. Phys. 122, 034104 (2005). doi:10.1063/1.1809605] is one of the most stable and efficient correlated OEP approaches. In this work, we introduce its scaled-opposite-spin (SOS) variant, named OEP2-SOS-sc. This new method further improves over the OEP2-sc for various properties, including correlation potentials, relaxed densities, and energies, fully retaining the good stability of the original approach. Thus, the OEP2-SOS-sc is an efficient and promising tool for high-level density functional theory simulations.