| 1. |
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| 2. |
- Finzel, Kati, et al.
(författare)
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A simple model for the Slater exchange potential and its performance for solids
- 2017
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Ingår i: International Journal of Quantum Chemistry. - : WILEY-BLACKWELL. - 0020-7608 .- 1097-461X. ; 117:1, s. 40-47
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Tidskriftsartikel (refereegranskat)abstract
- A simple local model for the Slater exchange potential is determined by least square fit procedure from Hartree-Fock (HF) atomic data. Since the Slater potential is the exact exchange potential yielding HF electron density from Levy-Perdew-Sahni density functional formalism (Levy et al., Phys. Rev. A 1984, 30, 2745), the derived local potential is significantly more negative than the conventional local density approximation. On the set of 22 ionic, covalent and van der Waals solids including strongly correlated transition metal oxides, it has been demonstrated, that this simple model potential is capable of reproducing the band gaps nearly as good as popular meta GGA potentials in close agreement with experimental values.
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| 3. |
- Finzel, Kati
(författare)
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About the atomic shell structure in real space and the Pauli exclusion principle
- 2016
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Ingår i: Theoretical Chemistry accounts. - : SPRINGER. - 1432-881X .- 1432-2234. ; 135:6, s. 148-
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that any set of eigenfunctions (1s, 2s) of a bare Coulomb Hamiltonian exhibit the same atomic shell structure pattern for the real-space indicator a(1), which is defined as the ratio between the positive kinetic energy density and the electron density. Since this model Hamiltonian excludes all effects due to the electron-electron repulsion, the appearance of the atomic shell structure is attributed to the Pauli exclusion principle that arises from the requirements for a fermionic wavefunction. Since the derivation is independent of the nuclear charge and the energy of the system, reversely imposing proper atomic shell structure behavior in the design of kinetic energy functionals mimics the Pauli exclusion principle during a variational process.
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| 4. |
- Finzel, Kati
(författare)
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About the compatibility between ansatzes and constraints for a local formulation of orbital-free density functional theory
- 2017
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Ingår i: International Journal of Quantum Chemistry. - : WILEY-BLACKWELL. - 0020-7608 .- 1097-461X. ; 117:5
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Tidskriftsartikel (refereegranskat)abstract
- Functional properties that are exact for the Hohenberg-Kohn functional may turn into mutually exclusive constraints at a given level of ansatz. This is exemplarily shown for the local density approximation. Nevertheless, it is possible to reach exactly the Kohn-Sham data from an orbital-free density functional framework based on simple one-point functionals by starting from the Levy-Perdew-Sahni formulation. The energy value is obtained from the density-potential pair, and therefore does not refer to the functional dependence of the potential expression. Consequently, the potential expression can be obtained from any suitable model and is not required to follow proper scaling behavior.
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| 5. |
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| 6. |
- Finzel, Kati
(författare)
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Approximating the Pauli Potential in Bound Coulomb Systems
- 2016
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Ingår i: International Journal of Quantum Chemistry. - : WILEY-BLACKWELL. - 0020-7608 .- 1097-461X. ; 116:16, s. 1261-1266
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Tidskriftsartikel (refereegranskat)abstract
- It is shown that the Pauli potential in bound Coulomb systems can in good approximation be composed from the corresponding atomic fragments. This provides a simple and fast procedure how to generate the Pauli potential in bound systems, which is needed to perform an orbital-free density functional calculation. The method is applicable to molecules and solids. (c) 2016 Wiley Periodicals, Inc.
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| 7. |
- Finzel, Kati, et al.
(författare)
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Efficient algorithms for Hirshfeld-I charges
- 2015
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Ingår i: Journal of Chemical Physics. - : AMER INST PHYSICS. - 0021-9606 .- 1089-7690. ; 143:8, s. 084115-
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Tidskriftsartikel (refereegranskat)abstract
- A new viewpoint on iterative Hirshfeld charges is presented, whereby the atomic populations obtained from such a scheme are interpreted as such populations which reproduce themselves. This viewpoint yields a self-consistent requirement for the Hirshfeld-I populations rather than being understood as the result of an iterative procedure. Based on this self-consistent requirement, much faster algorithms for Hirshfeld-I charges have been developed. In addition, new atomic reference densities for the Hirshfeld-I procedure are presented. The proposed reference densities are N-representable, display proper atomic shell structure and can be computed for any charged species.
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| 8. |
- Finzel, Kati, et al.
(författare)
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Energy-Surfaces from the Upper Bound of the Pauli Kinetic Energy
- 2016
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Ingår i: International Journal of Quantum Chemistry. - : WILEY-BLACKWELL. - 0020-7608 .- 1097-461X. ; 116:18, s. 1337-1341
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Tidskriftsartikel (refereegranskat)abstract
- Based on the Kohn-Sham Pauli potential and the Kohn-Sham electron density, the upper bound of the Pauli kinetic energy is tested as a suitable replacement for the exact Pauli kinetic energy for application in orbital-free density functional calculations. It is found that bond lengths for strong and moderately bound systems can be qualitatively predicted, but with a systematic shift toward larger bond distances with a relative error of 6% up to 30%. Angular dependence of the energy-surface cannot be modeled with the proposed functional. Therefore, the upper bound model is the first parameter-free functional expression for the kinetic energy that is able to qualitatively reproduce binding curves with respect to bond distortions. (C) 2016 Wiley Periodicals, Inc.
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| 9. |
- Finzel, Kati, et al.
(författare)
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Functional constructions with specified functional derivatives
- 2016
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Ingår i: Theoretical Chemistry accounts. - : SPRINGER. - 1432-881X .- 1432-2234. ; 135:12
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Tidskriftsartikel (refereegranskat)abstract
- A bifunctional construction depending on a specified density-potential pair and an approximate guiding electron density functional is presented. The proposed bifunctional construction properly transforms under homogeneous coordinate scaling and yields the specified functional derivative, which determines the electron density. Whereas the method is general and applicable to all functional types, it will prove especially helpful in the context of orbital-free density functional theory, where most existing approximate density functionals predict inaccurate potentials.
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| 10. |
- Finzel, Kati
(författare)
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Local conditions for the Pauli potential in order to yield self-consistent electron densities exhibiting proper atomic shell structure
- 2016
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Ingår i: Journal of Chemical Physics. - : AMER INST PHYSICS. - 0021-9606 .- 1089-7690. ; 144:3, s. 034108-
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Tidskriftsartikel (refereegranskat)abstract
- The local conditions for the Pauli potential that are necessary in order to yield self-consistent electron densities from orbital-free calculations are investigated for approximations that are expressed with the help of a local position variable. It is shown that those local conditions also apply when the Pauli potential is given in terms of the electron density. An explicit formula for the Ne atom is given, preserving the local conditions during the iterative procedure. The resulting orbital-free electron density exhibits proper shell structure behavior and is in close agreement with the Kohn-Sham electron density. This study demonstrates that it is possible to obtain self-consistent orbital-free electron densities with proper atomic shell structure from simple one-point approximations for the Pauli potential at local density level. (C) 2016 AIP Publishing LLC.
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