A self-interaction-free local hybrid functional: accurate binding energies vis-à-vis accurate ionization potentials...

Area of Science:

• Computational chemistry
• Quantum mechanics
• Materials science

Background:

• Density functional theory (DFT) is crucial for electronic structure calculations.
• Accurate approximation of exchange-correlation (xc) energy is key to DFT's success.
• Existing functionals often struggle with self-interaction errors and accurate ionization potential prediction.

Purpose of the Study:

• To introduce and evaluate a novel xc functional approximation for Kohn-Sham DFT.
• To assess the functional's ability to yield accurate binding energies and reliable Kohn-Sham eigenvalues.
• To investigate the trade-offs between accuracy in binding energies and ionization potentials.

Main Methods:

• Development of a local-hybrid functional combining exact exchange with non-local correlation.
• Ensuring the functional is free from one-electron self-interaction and satisfies scaling constraints.
• Testing the functional on atoms and small molecules, optimizing a free parameter.

Main Results:

• The new functional achieves accurate binding energies upon parameter optimization.
• Improvements observed in dissociation energy curves and Kohn-Sham eigenvalues.
• The functional's ability to accurately predict experimental ionization potentials was not satisfactory.

Conclusions:

• The developed functional shows promise for accurate binding energy calculations in DFT.
• Further development is needed to improve the prediction of ionization potentials.
• Findings provide context for ongoing research in xc functional development.