Implementing the mechanical force into the conceptual DFT framework: understanding and predicting molecular...

Area of Science:

• Chemistry
• Molecular Physics
• Theoretical Chemistry

Background:

• Molecular mechanochemistry explores chemical changes induced by mechanical energy at the single-molecule level.
• This contrasts with traditional energy inputs like heat (thermochemistry), electricity (electrochemistry), or light (photochemistry).

Purpose of the Study:

• To present a theoretical approach for predicting chemical property changes in molecules subjected to external mechanical force.
• To establish a framework for understanding mechanochemical reactivity based on fundamental molecular properties.

Main Methods:

• Utilized conceptual density functional theory (DFT) to analyze molecular energy perturbations under external stretching force (Fext).
• Developed mechanochemical response indices to quantify changes in chemical properties like hardness and electrophilicity.
• Investigated diatomic molecules to rationalize trends based on ground-state geometry and frontier molecular orbitals.

Main Results:

• Derived mechanochemical response indices that correlate with changes in molecular hardness and electrophilicity.
• Rationalized observed trends in diatomic molecules by linking them to electronic structure and geometry.
• Established a theoretical basis for predicting how mechanical force influences chemical reactivity.

Conclusions:

• The theoretical approach successfully predicts changes in chemical properties due to mechanical force.
• A set of predictive rules for polyatomic molecules was developed, extending the applicability of mechanochemical principles.
• This work provides a foundation for understanding and controlling chemical reactions through mechanical energy input.