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RESEARCH PRODUCT
Towards nonlocal density functionals by explicit modelling of the exchange-correlation hole in inhomogeneous systems
Klaas J. H. GiesbertzR. Van LeeuwenU. Von Barthsubject
FOS: Physical sciences02 engineering and technologyElectronClassification of discontinuities01 natural sciencesDFTCondensed Matter - Strongly Correlated ElectronsAtomic orbitalQuantum mechanicsPhysics - Chemical Physics0103 physical sciencesPhysics - Atomic and Molecular ClustersSDG 7 - Affordable and Clean Energy010306 general physicsEnergy functionalChemical Physics (physics.chem-ph)PhysicsQuantum Physics/dk/atira/pure/sustainabledevelopmentgoals/affordable_and_clean_energyStrongly Correlated Electrons (cond-mat.str-el)ta114theoretical nanoscienceFunction (mathematics)021001 nanoscience & nanotechnologyAtomic and Molecular Physics and OpticsCondensed Matter - Other Condensed MatterDensity functional theorySum rule in quantum mechanicsLocal-density approximationAtomic and Molecular Clusters (physics.atm-clus)Quantum Physics (quant-ph)0210 nano-technologyOther Condensed Matter (cond-mat.other)description
We put forward new approach for the development of a non-local 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 non-local density functional provides a significant improvement over the local density approximation.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2013-02-01 | Physical Review A |