Maximum bonding fragment orbitals for deciphering complex chemical interactions.

Area of Science:

• Quantum Chemistry
• Chemical Bonding Theory

Background:

• Describing complex chemical bonding situations requires sophisticated theoretical frameworks.
• Existing methods may struggle to provide clear, quantitative insights into intricate bonding interactions.

Purpose of the Study:

• To propose an optimal set of fragment orbitals for a general description of complex bonding.
• To develop a method for decomposing total bond order into well-defined pairwise orbital interactions.

Main Methods:

• Decomposition of total bond order between fragments into components.
• Identification of bonding between pairs of optimal fragment orbitals.
• Construction of doubly occupied bond orbitals to describe inter-fragment chemical bonding.

Main Results:

• A novel approach to separate complex bonding into simple pairwise orbital interactions.
• Development of quantitative orbital interaction diagrams.
• Analytical expressions for bond orders, polarities, occupancies, and orbital interaction energies.

Conclusions:

• The proposed method offers a simple and powerful tool for analyzing diverse chemical interactions (covalent, ionic, noncovalent).
• Provides new insights into the bond order concept and molecular orbital theory.
• Enables clear correlation of orbital interactions for a deeper understanding of chemical bonding.