RPBE

RPBE, short for Revised Perdew–Burke–Ernzerhof, is a generalized gradient approximation (GGA) exchange-correlation functional used in density functional theory (DFT). It is a modification of the PBE functional designed to improve the description of chemisorption and surface energetics on transition-metal surfaces. The principal adjustment concerns the exchange enhancement factor F_x(s): RPBE reduces the attraction of exchange at moderate reduced gradients s compared to PBE, while keeping the PBE correlation form. The net effect is generally to decrease the overbinding of adsorbates predicted by PBE, yielding adsorption energies and reaction energetics that are often closer to experimental values for surface systems.

RPBE has been widely adopted in surface science and catalysis studies, particularly for reactions occurring on metal surfaces such as CO, O, and H adsorption on Pt, Pd, Cu, and Ni. It is commonly used with plane-wave basis sets and pseudopotentials or projector-augmented wave methods.

Limitations include that, like other GGAs, RPBE does not inherently account for dispersion interactions; for systems where van der Waals forces are important, dispersion corrections or more advanced functionals may be needed. Its performance can vary across properties; while adsorption energies are often improved relative to PBE, bulk properties such as lattice constants and cohesive energies may not be more accurate. As with any functional, results should be cross-checked with other exchange-correlation approximations appropriate to the system of interest.

See also: PBE, PBEsol, DFT, surface science, catalysis.