Random phase approximation correlation energies with exact Kohn–Sham exchange

Abstract

The random phase approximation (RPA) correlation energy is expressed in terms of the exact local Kohn–Sham (KS) exchange potential and corresponding adiabatic and nonadiabatic exchange kernels for density-functional reference determinants. The approach naturally extends the RPA method in which, conventionally, only the Coulomb kernel is included. By comparison with the coupled cluster singles doubles with perturbative triples method it is shown for a set of small molecules that the new RPA method based on KS exchange yields correlation energies more accurate than RPA on the basis of Hartree–Fock exchange.

Keywords:

• random phase approximation
• exact exchange
• Kohn–Sham
• orbital-dependent functional
• exact exchange kernel

Acknowledgements

The authors gratefully acknowledge the funding of the German Research Council (DFG), which, within the framework of its ‘Excellence Initiative’, supports the Cluster of Excellence ‘Engineering of Advanced Materials’ (www.eam.uni-erlangen.de) at the University of Erlangen-Nuremberg.