Identifying a real space measure of charge-shift bonding with probability density analysis

Area of Science:

• Quantum Chemistry
• Chemical Bonding Theory

Background:

• Charge-shift bonds are hypothesized as a third type of chemical bond beyond covalent and ionic bonds.
• Valence bond theory identifies charge-shift bonds via resonance energy from ionic contributions.
• A clear real-space fingerprint for charge-shift bonding is currently lacking.

Purpose of the Study:

• To develop a real-space measure for identifying charge-shift bonding.
• To demonstrate the utility of probability density analysis for characterizing chemical bonds.
• To support the concept of charge-shift bonding with a novel indicator.

Main Methods:

• Utilizing probability density analysis, a real-space method based on the many-electron probability density |Ψ|².
• Applying barriers of a probability potential, previously shown to measure delocalization and covalent bonding.
• Analyzing numerous molecular examples to validate the proposed measure.

Main Results:

• A well-suited measure for charge-shift bonding was defined within probability density analysis.
• The new measure correlates strongly with charge-shift resonance energy from valence bond theory.
• The developed measure is independent of the reference state and bond polarity.

Conclusions:

• The study provides strong support for the charge-shift bonding concept through a novel real-space indicator.
• Probability density analysis offers a robust method for identifying and characterizing charge-shift bonds.
• This new measure allows for the characterization of chemical bonds by both polarity and charge-shift character.