Generalized gradient approximation bridging the rapidly and slowly varying density regimes: A PBE-like functional for hybrid interfaces

We propose a generalized gradient approximation constructed for hybrid interfaces, which is based on the Perdew, Burke, Ernzerhof (PBE) functional form and interpolates between the rapidly PBE and slowly varying (PBEsol, the revised PBE for solid-state systems) density regimes. This functional approximation (named PBEint) recovers the right second-order gradient expansion of the exchange energy and is accurate for jellium surfaces, interacting jellium slabs, molecules, solids, and metal-molecule interfaces.