Towards nonlocal density functionals by explicit modelling of the exchange-correlation hole in inhomogeneous systems
Giesbertz, K., van Leeuwen, R., & von Barth, U. (2013). Towards nonlocal density functionals by explicit modelling of the exchange-correlation hole in inhomogeneous systems. Physical Review A, 87(2), Article 022514. https://doi.org/10.1103/PhysRevA.87.022514
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2013Copyright
© 2013 American Physical Society. Published in this repository with the kind permission of the publisher.
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 −1 electron, (2) the
xc potential has the asymptotic −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.
...
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