Symmetry Breaking within Fermi-Löwdin Orbital Self-Interaction Corrected Density Functional Theory

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Materials Science

Background:

• Density Functional Theory (DFT) is a powerful tool for electronic structure calculations.
• Self-interaction error (SIE) is a known limitation in standard DFT approximations.
• Fermi-Löwdin orbital self-interaction correction (FLO-SIC) aims to mitigate SIE.

Purpose of the Study:

• To investigate the performance of FLO-SIC DFT for small molecules.
• To analyze the tendency of FLO-SIC to favor symmetric molecular geometries.
• To identify and discuss instances of symmetry breaking within FLO-SIC calculations.

Main Methods:

• Application of Fermi-Löwdin orbital self-interaction corrected density functional theory (FLO-SIC DFT).
• Calculations performed on molecules: C3H5, NO3-, O3, and CH3.
• Analysis of molecular geometries and electronic density distributions.

Main Results:

• FLO-SIC generally favors symmetric configurations for molecules with complex bonding.
• Symmetry breaking was observed in ozone (O3), potentially due to correlation energy treatment.
• The methyl radical (CH3) exhibited geometric distortion, indicating a different type of symmetry breaking.

Conclusions:

• FLO-SIC shows promise in reducing self-interaction errors and promoting molecular symmetry.
• Observed symmetry breaking artifacts highlight limitations in current approximate DFT functionals.
• Further development of DFT functionals and extensions of the FLO-SIC method are crucial for accurate predictions.