Coverage of dynamic correlation effects by density functional theory functionals: density-based analysis for neon

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Theoretical Chemistry

Background:

• Linking dynamic electron correlation in wave function theories (WFTs) with density functional theory (DFT) functionals is challenging.
• Nondynamic correlation effects are negligible for the Ne atom, simplifying analysis.

Purpose of the Study:

• Analyze dynamic electron correlation effects on electron density.
• Compare ab initio and DFT methods for calculating these effects.
• Inform the development of new DFT exchange-correlation functionals.

Main Methods:

• Employed a density-based approach using difference radial-density (DRD) distributions.
• Calculated DRD distributions for the Ne atom.
• Compared ab initio results with various DFT functionals, including OEP2.
• Addressed basis-set incompleteness errors.

Main Results:

• Dynamic correlation effects are largely captured by exchange-only DFT calculations for local, GGAs, and hybrid functionals.
• VWN5 and LYP correlation functionals show minimal dynamic correlation effects on density.
• Orbital-dependent OEP2 correlation functional accurately represents dynamic correlation effects.
• Self-interaction corrected calculations confirm findings are not artifacts.

Conclusions:

• Density-based criteria are valuable for developing improved DFT exchange-correlation functionals.
• Differences between energy- and density-based perspectives highlight the utility of density-based approaches.