Exchange-correlation potential built on the derivative discontinuity of electron density

Area of Science:

• Quantum Chemistry
• Computational Materials Science
• Electronic Structure Theory

Background:

• The exchange-correlation (XC) potential is crucial for accurately describing electronic structures in quantum chemistry.
• Existing methods for constructing XC potentials have limitations in reliability and predictive power.
• Developing accurate XC potentials is essential for understanding molecular properties and chemical reactions.

Purpose of the Study:

• To develop a novel, first-principle method for constructing reliable exchange-correlation (XC) potentials.
• To utilize the derivative discontinuity of electron density as a key constraint for potential construction.
• To assess the accuracy and potential improvements of the newly developed XC potentials.

Main Methods:

• A new method was developed to construct XC potentials by mixing exact exchange and local density approximation potentials in real space.
• A spatially dependent mixing parameter was derived based on the derivative discontinuity of electron density.
• Equations for solving the mixing parameter were derived, and an approximation was proposed for simplification.

Main Results:

• The proposed method, using an approximation, yielded reasonable predictions for ionization energies, fundamental gaps, and singlet-triplet energy differences in various molecular systems.
• The impact of the approximation on the XC potentials was analyzed, indicating that removing it could further enhance potential quality.
• The derivative discontinuity of electron density proved to be a valuable constraint for creating high-quality XC potentials.

Conclusions:

• The developed method offers a promising route to constructing reliable exchange-correlation potentials.
• The derivative discontinuity of electron density is a key physical quantity for improving XC potential accuracy.
• Further refinement by removing the proposed approximation can lead to even higher quality XC potentials for electronic structure calculations.