Local Exchange Integrand: Looking into Quantum Contributions to Chemical Bonds

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Chemical Bonding Theory

Background:

• Understanding quantum corrections in chemical bonding is crucial.
• The exchange energy integrand, K(r1,r2), offers insights into these corrections.
• Visualizing K(r1,r2) in terms of atomic contributions can improve interpretability.

Purpose of the Study:

• To present atomic contribution maps of the exchange energy integrand K(r1,r2).
• To develop a vocabulary for identifying regions affected by exchange corrections.
• To apply these maps to understand halogen bonding and σ-hole anisotropy.

Main Methods:

• Calculation and mapping of the exchange energy integrand K(r1,r2) based on atomic contributions.
• Analysis of diatomic molecules (covalent and noncovalent) to establish descriptive vocabularies.
• Application to halogen-bonded complexes and validation using molecular orbital, NBO, and SAPT(DFT) methods.

Main Results:

• Maps of K(r1,r2) provide atomic-level insights into exchange energy contributions.
• Identified specific regions where exchange corrections modify electron density predictions.
• Demonstrated improved understanding of halogen bond interactions and σ-hole characteristics.

Conclusions:

• Atomic contribution maps of K(r1,r2) are valuable tools for chemical bond analysis.
• This approach enhances the description of electron distribution influenced by quantum effects.
• The findings support the utility of K(r1,r2) for detailed molecular interaction studies.