On the Interplay between Nuclear-Nuclear Repulsion and the Electronic Components of the Reaction Force

Area of Science:

• Computational chemistry
• Theoretical chemistry
• Chemical reaction dynamics

Background:

• The reaction force (RF) formalism analyzes energy changes during chemical reactions.
• Current RF interpretations can present conceptual challenges in physical clarity.
• Decomposition of total energy along reaction paths lacks intuitive physical insight.

Purpose of the Study:

• To elucidate the roles of electronic and nuclear repulsion energies in reaction barriers.
• To introduce a novel RF decomposition scheme for enhanced clarity.
• To provide a transparent framework for partitioning reaction forces.

Main Methods:

• Developed an a priori separation of total energy into electronic and nuclear repulsion contributions.
• Introduced a novel reaction force decomposition scheme.
• Examined five simple chemical reactions to validate the method.

Main Results:

• The novel RF scheme partitions forces into electronic rearrangement and internuclear repulsion zones.
• Nuclear-nuclear repulsion (Vnn) shows a double-maxima profile along the reaction path.
• Electronic energy (Ee) exhibits a double-minima profile along the reaction path.
• Force components demonstrated general behavior across studied reactions.

Conclusions:

• The proposed method offers a more intuitive and reliable framework for analyzing reaction mechanisms.
• Distinguishes clearly between electronic reorganization and geometric changes.
• Confirms physical insights through contrasting energy profiles.