Electronic structure methods based on the random phase approximation (RPA) provide a systematic way for improvement over the semi-local density functional theory (DFT). RPA is computationally less expensive compared to the wave function based MP2 method but is significantly more accurate. One of the systematic ways to improve the RPA correlation energy is to reduce the dependence on the reference KS determinant through orbital optimization. In this study, the orbital optimized RPA (oRPA) method is applied to calculate the potential energy surfaces of noble gas dimers and open shell systems such as complexes of He/Ne with OH radical and Li dimer. The oRPA method is found to improve the binding energies for these van der Waals complexes over the RPA energies. Furthermore, it also removes the unphysical energy barrier in case of the Be dimer.

Non-covalent interactions using orbital optimized random-phase approximation

251st National Meeting (2016)

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