Correcting the Charge Delocalization Error of Density Functional Theory.

Area of Science:

• Quantum Chemistry
• Computational Materials Science
• Theoretical Chemistry

Background:

• Density functional theory (DFT) struggles with charge delocalization errors and nondynamic correlation.
• Existing DFT functionals inaccurately model dissociation of charged dimers and delocalize charges in clusters.
• These errors impact the accuracy of predicting properties for charged molecular systems.

Purpose of the Study:

• To develop a novel DFT functional addressing both charge delocalization and nondynamic correlation.
• To improve the accuracy of DFT for charged molecular systems and clusters.
• To reduce multielectron self-interaction errors in DFT calculations.

Main Methods:

• Modification of a functional designed for nondynamic correlation.
• Adjusting nondynamic correlation specifically for parallel spins.
• Testing the modified functional against established benchmarks like CCSD(T) and the SIE4x4 dataset.

Main Results:

• The new functional successfully eliminates charge delocalization errors and spurious barriers in charged dimer dissociation.
• It accurately localizes net positive charges in (CH4)+ clusters, predicting a constant ionization potential.
• Performance on the SIE4x4 set surpasses various contemporary DFT functionals.

Conclusions:

• The developed functional effectively treats charge delocalization errors concurrently with nondynamic correlation.
• This approach offers a significant advancement in the accuracy of DFT for charged systems.
• The findings demonstrate the feasibility of unified treatment for these persistent DFT challenges.