Does the derivative of the energy density functional provide a proper quantitative formulation of electronegativity?

TL;DR

This paper argues that the derivative of the energy density functional is not a valid measure of local electronegativity, despite its constant value in ground-state equilibrium systems.

Contribution

It critically evaluates the derivative of the energy density functional and demonstrates its inadequacy as a local electronegativity measure.

Findings

Derivative does not provide a valid local electronegativity measure

Constant value in ground-state systems is not sufficient for validity

Highlights limitations of energy density functional derivatives

Abstract

It is pointed out that the derivative of the energy density functional does not provide a valid local electronegativity measure, in spite of its appealing property of becoming constant for ground-state equilibrium systems.