Binding energy curves from nonempirical density functionals II: Van der Waals bonds in rare-gas and alkaline-earth diatomics

The binding energy curves for Ne2, Ar2 and Be2 are computed with several nonempirical density functionals, including the local spin density (LSD) approximation, the Perdew-Burke-Ernzerhof (PBE), generalized gradient approximation (GGA), and the Tao-Perdew-Staroverov-Scuseria (TPSS) meta GGA. Binding energy curves in reasonable agreement with those constructed from experiment are found from PBE and TPSS describing the short-range part of van der Waals interaction.