Multiconfiguration Pair-Density Functional Theory Is Free From Delocalization Error.

Area of Science:

• Quantum Chemistry
• Computational Physics
• Electronic Structure Theory

Background:

• Delocalization error is a significant limitation in conventional Kohn-Sham density functional theory (KS-DFT) approximations.
• This error arises from the incorrect delocalization of electrons in theoretical models.
• Identifying and correcting such errors is crucial for advancing computational chemistry methods.

Purpose of the Study:

• To evaluate the performance of multiconfiguration pair-density functional theory (MC-PDFT) regarding delocalization error.
• To compare MC-PDFT with various traditional and modern Kohn-Sham density functionals.
• To establish MC-PDFT as a potential improvement over existing KS-DFT methods.

Main Methods:

• Calculation of vertical first ionization energies for well-separated Helium (He) clusters.
• Application of multiconfiguration pair-density functional theory (MC-PDFT).
• Comparative analysis with established Kohn-Sham density functional theory (KS-DFT) functionals.

Main Results:

• MC-PDFT demonstrates freedom from delocalization error in the studied systems.
• Conventional KS-DFT functionals universally exhibit significant delocalization errors.
• Recent corrected functionals show improvement but MC-PDFT offers a more fundamental solution.

Conclusions:

• MC-PDFT effectively removes delocalization error, a key advantage over standard KS-DFT.
• This finding positions MC-PDFT as a significant advancement beyond current KS-DFT.
• MC-PDFT holds considerable promise for future high-accuracy electronic structure computations.