ωB2PLYP & ωB2GPPLYP: the first two double-hybrid density functionals with long-range correction optimized for excitation energies.

Abstract

Double-hybrid density functionals are currently the most accurate density functionals for ground-state properties and electronic excitations. Nevertheless, the lack of a long-range correction scheme makes them unreliable when it comes to long-range excitations. For this reason, we propose the first two time-dependent double-hybrid functionals with correct asymptotic long-range behavior named ωB2PLYP and ωB2GPPLYP. Herein, we demonstrate their excellent performance and show that they are the most accurate and robust time-dependent density functional theory methods for electronic excitation energies. They provide a balanced description of local-valence, Rydberg and charge-transfer states. They are also able to tackle the difficult first two transitions in polycyclic aromatic hydrocarbons, and show very promising results in a preliminary study on transition metal compounds, exemplified for titanium dioxide clusters. This work shows that double hybrids can be systematically improved also for excitation energies and further work in this field is warranted.