Perturbed reactivity descriptors in the grand canonical ensemble

Departing from the framework provided by the grand canonical ensemble, the conceptual density functional theory reactivity indexes for isolated systems are modified to incorporate through a first order perturbation approach the effects on them induced by the presence of another interacting species. The general procedure established leads to the same perturbed expressions for the chemical potential and the hardness previously developed and allows one to derive the perturbed expressions for the Fukui function and the dual descriptor. The expressions obtained include the effects on the reactivity indexes of a given species when it interacts with another one, through additional parameters that can be determined to satisfy known specific conditions associated with the interacting systems studied, to improve the description of their chemical reactivity.