Chemical bonding: the orthogonal valence-bond view

Area of Science:

• Quantum Chemistry
• Theoretical Chemistry
• Computational Chemistry

Background:

• Chemical bonding involves local charge and spin reorganization.
• Multi-configurational self-consistent field (MCSCF) wave functions obscure local bonding information due to delocalized molecular orbitals (MOs).
• Valence bond (VB) wave functions offer a localized perspective on chemical bonding.

Purpose of the Study:

• To reveal hidden local information in MCSCF wave functions through transformation into VB wave functions.
• To analyze the influence of atomic and symmetry changes on chemical reactions.
• To explore the interpretational advantages of orthogonal VB wave functions.

Main Methods:

• Transformation of MCSCF wave functions into orthogonal VB wave functions (VB reading).
• Analysis of four chemical reactions using this transformation.
• Investigation of how changes in atoms and local symmetry affect reaction pathways.

Main Results:

• The VB reading of MCSCF wave functions successfully reveals local bonding information.
• Changes in atomic composition and local symmetry were shown to influence chemical reactions.
• Orthogonal VB wave functions provide a clearer interpretation of electronic situations compared to non-orthogonal ones.

Conclusions:

• The transformation to orthogonal VB wave functions is crucial for understanding localized chemical processes.
• This method uncovers bonding properties that are otherwise undetectable.
• The approach offers new insights into reaction mechanisms and the role of atomic and symmetry factors.