Systematically Improvable Generalization of Self-Interaction Corrected Density Functional Theory.

Area of Science:

• Quantum Chemistry
• Computational Physics
• Materials Science

Background:

• Density functional theory (DFT) approximations lack systematic improvability.
• Perdew-Zunger self-interaction correction (PZSIC) aims to improve DFT but can paradoxically degrade performance.
• Existing DFT methods struggle with strongly correlated systems.

Purpose of the Study:

• To derive a systematically improvable density functional theory (DFT) approximation.
• To bridge the gap between DFT and exact wave function theory.
• To develop accurate and computationally efficient methods for strongly correlated systems.

Main Methods:

• Utilizing the adiabatic projection formalism.
• Deriving Perdew-Zunger self-interaction correction (PZSIC) via a reference system with electron self-interaction.
• Generalizing to "self-and-some-others" interaction to incorporate correlation.

Main Results:

• A novel derivation of PZSIC is presented.
• A systematic pathway from PZSIC to exact wave function theory is established, avoiding double counting of correlation.
• Minimal active spaces are shown to accurately treat challenging electronic systems.

Conclusions:

• The adiabatic projection formalism provides a route to systematically improvable DFT.
• The developed method offers a computationally tractable approach for strongly correlated systems.
• This work advances the accuracy and applicability of electronic structure calculations.