Communication: One third: A new recipe for the PBE0 paradigm

Abstract

We analyze the performances of the parameter-free hybrid density functional PBE0-1/3 obtained combining the PBE generalized-gradient functional with a predefined amount of exact exchange of 1/3, as recently discussed by Cortona [J. Chem. Phys. 136, 086101 (2012)]. The numerical results that we have obtained for various properties, such as atomization energies (G2-148 dataset), weak interactions (NCB31 dataset), hydrogen-bond length optimizations, and dissociation energies (HB10 dataset), and vertical excitation energies, show an increased performance of PBE0-1/3 with respect to the widely used PBE0. We therefore propose to use one third as the mixing coefficient for the PBE-based hybrid functional.

Double-hybrid density functionals: merging wavefunction and density approaches to get the best of both worlds

“…It is worth to mention that very recently a different λ-dependence has been proposed, leading to a different integer for n [29,30].…”

Understanding the role of vibrations, exact exchange, and many-body van der Waals interactions in the cohesive properties of molecular crystals

“…Indeed, recently it has been suggested that a fraction of 1/3 exact exchange should be used as the PBEbased hybrid functional. 75 In addition, screened hybrids such as the Heyd, Scuseria, and Ernzerhof (HSE) functional 76 might be more computationally efficient and accurate in some cases, although their effect on molecular-crystal lattice energies is largely unknown. It is likely that for many of the hydrogen-bonded systems the lattice energy could be tuned with differing amounts of exact exchange and/or screening, as different systems have different hydrogen-bond strengths and therefore de-localisation.…”

Describing excited states of [n]cycloparaphenylenes by hybrid and double-hybrid density functionals: from isolated to weakly interacting molecules

“…Whereas for hybrid (e.g. PBE0 [52] or PBE0-1/3 [53]) density functionals the excitation energies Ω are obtained following the standard formalism, which have been thoroughly benchmarked in last years [54,55], an additional correction is however needed for the case of double-hybrid (e.g. PBE0-DH or PBE-QIDH) models [56], with the form:…”