Feynman Force Analysis of Chemical Processes in Terms of Topological Atomic Contributions

Abstract

The nature of the chemical bond is analyzed in terms of the atomic contributions to the Feynman forces using the Quantum Theory of Atoms in Molecules and the Interacting Quantum Atoms method. This approach provides a means for quantifying the relationship between the atomic electronic reorganization and the evolution of functional group interactions with the forces exerted on the nuclear framework during a chemical transformation. Using this decomposition scheme, the forces driving a chemical process are locally assigned to atoms or functional group contributions. The interatomic component of the forces can be ascribed as bonding forces; their exchange-correlation and electrostatic contributions reveal the nature of the interactions affecting the forces on the nuclei. This method is used to analyze the chemical interactions involved in the formation of ground and excited state diatomic molecules, the prototropism of formamide, the Diels−Alder cycloaddition of 1,3-butadiene with ethylene, and the Jahn−Teller effect of hydrated transition metal complexes.

Interacting Quantum Atoms Analysis of the Reaction Force: A Tool to Analyze Driving and Retarding Forces in Chemical Reactions

“…Our approach is equivalent to that recently presented in Ref. [31] although we focus here on its relation to the reaction force formalism. It opens a chemical window to the global reaction force, whose power emanates from its invariance under orbital transformations and theoretical levels.…”

“…As already noticed, Jara-Cortés et al has used this partition to analyse proton transfer, Diels-Alder reaction and Jahn-Teller distortion, under the Feynmann forces perspective. [31] The Reaction Force view is examined now. Using the definition of reaction force given in eq.…”

“…[30] Coupling IQA to RF thus provides an independent, unique window to characterise driving and retarding forces associated with all the IQA chemical concepts, allowing for an extremely detailed view of the relevant energetic changes at each point of the potential energy curve. An equivalent scheme to the one provided here has recently been put forward, [31] focusing on the Hellmann-Feynman forces. Here we offer a different perspective in which these concepts are interwoven with the standard language of the Reaction Force.…”

Atoms in molecules in real space: a fertile field for chemical bonding

“…Thus, the IQA decomposition of F ( ξ ) into self-atomic/group components and classical/exchange–correlation interaction terms, which can be obtained through differentiation of cubic splines, yields chemically appealing images in terms of bonds, covalency and ionicity for different types of reactions. 160,161 Similar descriptions can be obtained with the closely-related Reduced Energy Gradient (REG) technique, 162 which relates the gradient of selected IQA components to the gradient of the total energy with respect to an arbitrary reaction coordinate for binding or reactive processes.…”