Elimination of Spurious Fractional Charges in Dissociating Molecules by Correcting the Shape of Approximate Kohn-Sham Potentials
| Autor: | Darya N. Komsa, Viktor N. Staroverov |
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| Rok vydání: | 2016 |
| Předmět: |
Electron density
010304 chemical physics Chemistry Kohn–Sham equations Charge (physics) 01 natural sciences Diatomic molecule Electric charge Computer Science Applications symbols.namesake Delocalized electron Heteronuclear molecule 0103 physical sciences Physics::Atomic and Molecular Clusters Rydberg formula symbols Physics::Chemical Physics Physical and Theoretical Chemistry Atomic physics 010306 general physics |
| Zdroj: | Journal of chemical theory and computation. 12(11) |
| ISSN: | 1549-9626 |
| Popis: | Standard density-functional approximations often incorrectly predict that heteronuclear diatomic molecules dissociate into fractionally charged atoms. We demonstrate that these spurious charges can be eliminated by adapting the shape-correction method for Kohn-Sham potentials that was originally introduced to improve Rydberg excitation energies [ Phys. Rev. Lett. 2012 , 108 , 253005 ]. Specifically, we show that if a suitably determined fraction of electron charge is added to or removed from a frontier Kohn-Sham orbital level, the approximate Kohn-Sham potential of a stretched molecule self-corrects by developing a semblance of step structure; if this potential is used to obtain the electron density of the neutral molecule, charge delocalization is blocked and spurious fractional charges disappear beyond a certain internuclear distance. |
| Databáze: | OpenAIRE |
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