Stationary conditions of the electron density along the reaction path: Connection with conceptual DFT and information theory

The Kohn-Sham density functional theory (DFT) formalism has been used to investigate the influence of the stationary behavior of the electron density (ρ(r;s)) along a minimum energy path on the corresponding stationary conditions observed in the total potential energy of the reactive system, information theory measures (Shannon information entropy and Onicescu information energy), and chemical reactivity indexes (the chemical hardness). The theoretical treatment presented in this work, combined with DFT calculations on 3 different test reactions: H' + H₂, H' + CH₄ and H- + CH₄, suggest that for any reactive system, properties that can be cast as a functional of the electron density, must exhibit stationary points along the IRC path modulated by the corresponding stationary behavior of the electron density.