2012/10/31 by Klaas J. H. Giesbertz, Robert van Leeuwen, Ulf von Barth
Earth and Planetary Sciences · Mathematics · Physics and Astronomy · #Advanced Chemical Physics Studies #Atomic orbital #Classification of discontinuities #Degeneracy (biology) #Density functional theory #Electron #Function (biology) #Functional derivative #High-pressure geophysics and materials #Hybrid functional #Local-density approximation #Mathematical analysis #Mathematics #Physics #Quantum mechanics #Spectroscopy and Quantum Chemical Studies #Statistical physics #cond-mat.other #cond-mat.str-el #physics.atm-clus #physics.chem-ph #quant-ph
paper · pdf · doi:10.1103/physreva.87.022514
published as Phys. Rev. A 87, 022514 (2013) · 14 pages, 7 figures
arxiv created 2013/02/20 · openalex publication_date 2013/02/27 · arxiv updated 2013/08/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We put forward an approach for the development of a nonlocal density functional by a direct modeling of the shape of exchange-correlation (xc) hole in inhomogeneous systems. The functional is aimed at giving an accurate xc energy and an accurate corresponding xc potential even in difficult near-degeneracy situations such as molecular bond breaking. In particular we demand that: (1) the xc hole properly contains \ensuremath-1 electron, (2) the xc potential has the asymptotic \ensuremath-1/r behavior outside finite systems, and (3) the xc potential has the correct step structure related to the derivative discontinuities of the xc energy functional. None of the currently existing functionals satisfies all these requirements. These demands are achieved by screening the exchange hole in such a way that the pair-correlation function is symmetric and satisfies the sum rule. These two features immediately imply (1) and (2) while the explicit dependence of the exchange hole on the Kohn-Sham orbitals implies (3). Preliminary calculations show an improved physical description of the dissociating hydrogen molecule. Though the total energy is still far from perfect, the binding curve from our nonlocal density functional provides a significant improvement over the local density approximation.