Atomic volumes and polarizabilities in density-functional theory

Area of Science:

• Quantum Chemistry
• Computational Physics

Background:

• The Becke-Johnson definition of atomic volume is used to derive atom-in-molecule polarizabilities from free-atom values.
• This method is applied within the nonempirical exchange-hole dipole moment model for dispersion interactions.

Purpose of the Study:

• To examine how basis sets and density-functional approximations affect Becke-Johnson atomic volumes.
• To establish a theoretical foundation for the Becke-Johnson atomic volume definition.
• To generate reference data for atomic volumes across all elements (H-Lr).

Main Methods:

• Systematic variation of basis sets.
• Evaluation of different density-functional approximations.
• Analysis of atomic volume calculations for elements Hydrogen through Lawrencium.

Main Results:

• The study quantifies the dependence of atomic volumes on computational parameters.
• Reference data for atomic volumes are presented for all elements.
• A theoretical justification for the Becke-Johnson definition is developed.

Conclusions:

• Understanding the impact of computational choices on atomic volumes is essential for accurate dispersion calculations.
• The provided reference data and theoretical foundation aid in the application of the Becke-Johnson method.