Screening in Orbital-Density-Dependent Functionals.

نویسندگان

  • Nicola Colonna
  • Ngoc Linh Nguyen
  • Andrea Ferretti
  • Nicola Marzari
چکیده

Electronic-structure functionals that include screening effects, such as Hubbard or Koopmans' functionals, are required to describe the response of a system to the fractional addition or removal of an electron from an orbital or a manifold. Here, we present a general method to incorporate screening based on linear-response theory, and we apply it to the case of orbital-by-orbital screening of Koopmans' functionals. We illustrate the importance of such generalization when dealing with challenging systems containing orbitals with very different chemical character, also highlighting the simple dependence of the screening on the localization of the orbitals. We choose a set of 46 transition-metal complexes for which experimental data and accurate many-body perturbation theory calculations are available. When compared to experiment, results for ionization potentials show a very good performance, with a mean absolute error of 0.2 eV, comparable to the most accurate many-body perturbation theory approaches. These results reiterate the role of Koopmans-compliant functionals as simple and accurate quasiparticle approximations to the exact spectral functional, bypassing diagrammatic expansions and relying only on the physics of the local density or generalized-gradient approximation.

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عنوان ژورنال:
  • Journal of chemical theory and computation

دوره   شماره 

صفحات  -

تاریخ انتشار 2018