Dissecting molecular descriptors into atomic contributions in density functional reactivity theory

Area of Science:

• * Quantum Chemistry
• * Computational Chemistry
• * Theoretical Chemistry

Background:

• * Density functional reactivity theory (DFRT) utilizes molecular electron density, gradient, and Laplacian to characterize molecular structure and reactivity.
• * Both global (molecular) and local (atomic) descriptions are crucial for a comprehensive understanding.
• * Previous work established intrinsic correlations between these quantities for atomic and molecular systems.

Purpose of the Study:

• * To investigate atomic contributions to global reactivity descriptors within DFRT.
• * To explore density-based quantification of steric effects and related indices.
• * To analyze the behavior of these descriptors during various bonding processes in hydrocarbon systems.

Main Methods:

• * Application of Bader's zero-flux partition scheme to analyze atomic contributions.
• * Implementation and validation of a novel basin-based integration algorithm.
• * Investigation of simple hydrocarbon systems undergoing stretching, bending, and rotating motions.

Main Results:

• * Confirmation of strong correlations between global reactivity descriptors for molecular systems.
• * Revelation of novel and unexpected changing patterns in atomic values of these descriptors.
• * Identification of distinct patterns for atomic and molecular descriptor values across different systems and bonding scenarios.

Conclusions:

• * The study validates the theoretical proof of strong correlations between global reactivity descriptors.
• * New atomic-level insights into chemical phenomena are provided through observed descriptor patterns.
• * The findings enhance the understanding of the origin and nature of chemical reactivity at the atomic scale.