Range-separated van der Waals density functional hybrids

Hybrid density functionals replace a fraction of an underlying exchange with a Fock-exchange component. They are successful in accurately describing a wide range of molecular and bulk properties. Range-separated hybrids (RSHs) also effectively screen the Fock-exchange component and thus open the door for characterizations of metals and of adsorption at metal surfaces. However, the inclusion of van der Waals (vdW) forces remains a challenge. We present a set of new RSHs within the framework of the vdW density functional (vdW-DF) method and based on an analytical-hole description of their gradient-corrected exchange components¹. Our most robust design termed vdW-DF-ahcx, is based on the consistent-exchange vdW-DF-cx version that leverages a Lindhard screening argument to balance exchange and correlation². It is set up to describe the adsorption of molecules at general surfaces. We test the performance of our vdW-DF RSHs on a broad set of molecular properties, bulk structure and cohesion, as well as bandgaps of semiconductors. Finally, we test the vdW-DF RSHs on the long-standing CO adsorption puzzle and we discuss the results.