Comment on "Density functional theory is straying from the path toward the exact functional".

Area of Science:

• Quantum Chemistry
• Computational Physics

Background:

• Density functional theory (DFT) is a key method in quantum chemistry.
• Recent functionals have been scrutinized for their accuracy.

Purpose of the Study:

• To evaluate claims that recent density functionals deviate from exactness.
• To assess the chemical relevance of observed deviations in specific systems.

Main Methods:

• Analysis of energy calculations for compact 1s² and 1s²2s² electronic systems.
• Comparison of DFT results with established energy benchmarks.

Main Results:

• DFT functionals show deviations for highly compact systems.
• These deviations are found to be system-specific and not chemically significant.
• The Hartree-Fock picture favors these compact systems, influencing the comparison.

Conclusions:

• The perceived "straying" of recent density functionals is not chemically relevant.
• Deviations are limited to specific, dense electronic systems and do not invalidate broader DFT applications.