vdW-DF-ahcx: a range-separated van der Waals density functional hybrid

Hybrid density functionals replace a fraction of an underlying generalized-gradient approximation (GGA) exchange description with a Fock-exchange component. Range-separated hybrids (RSHs) also effectively screen the Fock-exchange component and thus open the door for characterizations of metals and adsorption at metal surfaces. The RSHs are traditionally based on a robust GGA, such as PBE (Perdew J P et al 1996 Phys. Rev. Lett. 77 3865), for example, as implemented in the HSE design (Heyd J et al 2003 J. Chem. Phys. 118 8207). Here we define an analytical-hole (Henderson T M et al 2008 J. Chem. Phys. 128 194105) consistent-exchange RSH extension to the van der Waals density functional (vdW-DF) method (Berland K et al 2015 Rep. Prog. Phys. 78 066501), launching vdW-DF-ahcx. We characterize the GGA-type exchange in the vdW-DF-cx version (Berland K and Hyldgaard P 2014 Phys. Rev. B 89 035412), isolate the short-ranged exchange component, and define the new vdW-DF hybrid. We find that the performance vdW-DF-ahcx compares favorably to (dispersion-corrected) HSE for descriptions of bulk (broad molecular) properties. We also find that it provides accurate descriptions of noble-metal surface properties, including CO adsorption.

Automated summary

Hybrid density functionals use a fraction of a generalized-gradient approximation (GGA) exchange description combined with a Fock-exchange component. Range-separated hybrids (RSHs) screen the Fock-exchange component effectively, allowing for characterizations of metals and adsorption at metal surfaces. The vdW-DF-ahcx method, which is an analytical-hole consistent-exchange RSH extension to the vdW-DF method, shows comparable performance to HSE for bulk and noble-metal surface properties.