Ab Initio Calculation of Coupling-Constant Averaged Exchange-Correlation Holes for Spherically Symmetric Atoms

Area of Science:

• Computational chemistry
• Quantum mechanics
• Materials science

Background:

• Accurate exchange-correlation (XC) energy approximation is crucial for density functional theory (DFT) calculations.
• Model XC holes are used to develop XC approximations, but reliable reference data is scarce.
• Existing reference data is limited to a few specific electronic systems.

Purpose of the Study:

• To construct accurate coupling-constant averaged XC holes for spherically symmetric atoms.
• To resolve XC holes into individual exchange and correlation components.
• To provide a new dataset for evaluating and developing XC hole models.

Main Methods:

• Employed Lieb optimization with a coupled cluster singles and doubles (CCSD) reference.
• Calculated XC holes for five spherically symmetric atoms: He, Li, Be, N, and Ne.
• Resolved XC holes into exchange and correlation components.

Main Results:

• Generated accurate reference XC holes for He, Li, Be, N, and Ne.
• Compared generated data with Local Density Approximation (LDA) and Perdew-Burke-Ernzerhof (PBE) models.
• Confirmed LDA limitations and PBE improvements in hole depth and long-range decay.

Conclusions:

• The generated XC hole data serves as a valuable benchmark for DFT approximations.
• Analysis validates and explains the performance differences between LDA and PBE.
• Demonstrated real-space behavior of XC holes for atomic systems.