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Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
Tests of functionals for systems with fractional electron number
Oleg A Vydrov1, Gustavo E Scuseria, John P Perdew
1Department of Chemistry, Rice University, Houston, TX 77005, USA.
The Journal of Chemical Physics
|April 28, 2007
Summary
Common density functionals incorrectly model how ground state energy changes with electron number, leading to self-interaction error (SIE). This study quantizes SIE in various approximations, finding long-range corrected hybrids perform best for molecular properties.
Area of Science:
- Quantum Chemistry
- Computational Materials Science
Background:
- The exact theory predicts linear ground state energy dependence on electron number.
- Approximate density functionals often fail to reproduce this linearity, indicating self-interaction error (SIE).
Purpose of the Study:
- To quantify the many-electron SIE in various common approximate density functionals.
- To assess the impact of SIE on chemical phenomena like anion stability and charge transfer.
Main Methods:
- Calculations were performed on fractionally charged atoms to evaluate energy dependence on electron number.
- Various density functional approximations, including semilocal, global hybrids, and Hartree-Fock, were analyzed.
Main Results:
- Semilocal approximations exhibit the largest many-electron SIE, with only marginal improvement in global hybrids.
- The Perdew-Zunger self-interaction correction reduced SIE but decreased accuracy for equilibrium properties.
- Long-range corrected hybrid functionals demonstrated minimal SIE and strong performance for molecular properties.
Conclusions:
- Many-electron SIE is a significant issue in common density functional approximations.
- Long-range corrected hybrid functionals offer a promising approach to mitigate SIE while maintaining accuracy for molecular properties.
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