Different conventional (i.e. non-ML) charge equilibration and electronegativity equalization methods have been proposed in the literature. In the derivation of the charge equilibration approach we largely follow the formalism of Goedecker and coworkers, which is in turn based on the QEq method of Rappé and Goddard. In this context, QEq can be understood as a kind of semi-empirical, orbital-free density functional theory, where the electron density ρ(r) is expanded as: