The Many-Electron Perspective on Local Spins and their Implication for Chemical Bonding

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Chemical Bonding Theory

Background:

• Local spin is crucial for chemical bonding analysis but lacks a unique, observable definition.
• Existing methods for local spin evaluation are varied and often theory-dependent.

Purpose of the Study:

• To develop a general, theory-independent framework for evaluating local spin distributions.
• To directly link local spin properties to chemical bonding from the many-electron wave function.

Main Methods:

• Developed a framework within probability density analysis (PDA) to analyze the many-electron probability density |Ψ|².
• Explicitly accounted for spin multiplicity in the analysis.
• Applied the method to molecules with first-row elements and hydrogen.

Main Results:

• Covalent bonding is reflected in the exchange of opposite-spin electrons, altering local spin weights.
• Higher local spin states correlate with increased electron delocalization.
• Established clear links between local spin, molecular geometry, hybridization, and molecular orbital theory.

Conclusions:

• The developed PDA framework provides a theory-independent, real-space method for understanding local spin.
• This approach offers direct insights into chemical bonding from the many-electron wave function.