A new exchange-correlation functional free of delocalization and static correlation errors.

Area of Science:

• Quantum Chemistry
• Computational Physics
• Materials Science

Background:

• Predicting binding curves for H2(+) and H2 systems is a significant challenge in electronic density functional theory (DFT).
• Existing DFT functionals often struggle with delocalization and static correlation errors, leading to inaccurate predictions.

Purpose of the Study:

• To develop a novel density functional for exchange-correlation energy that addresses the limitations of current DFT methods.
• To improve the accuracy of binding curve predictions for small molecular systems, specifically H2(+) and H2.

Main Methods:

• A new functional was developed using the weighted density approximation and classical mapping method.
• The functional incorporates the exact sum rule for the exchange-correlation hole and accurate correlation functions of uniform electrons.
• The method was tested for one-electron systems and the binding energy of hydrogen atoms.

Main Results:

• The new functional eliminates delocalization and static correlation errors.
• It achieves exact results for all one-electron systems.
• The functional correctly predicts the asymptotic limit of the binding energy between hydrogen atoms.

Conclusions:

• The developed functional offers a significant improvement for DFT calculations involving H2(+) and H2 systems.
• This method provides a more accurate and reliable approach for predicting molecular binding energies.
• The functional's ability to handle one-electron systems and hydrogen binding energy suggests broader applicability in quantum chemistry.