An overview of physical and chemical long-range phenomena governed by Friedel oscillations: a bridge between physics and chemistry

Abstract

Friedel oscillations (FOs) are quantum mechanical phenomena observed as oscillatory variations in electron density due to the presence of impurity or defect in a medium containing electron gas. FOs profoundly influence surface properties, including the ordering of adsorbates and surface-mediated interactions crucial for catalytic activity. We delve into both experimental and theoretical aspects of FOs, organizing our discussion around the physicochemical systems of interest, the decay pattern, wavelength, and amplitude of FOs caused by different perturbations. Additionally, we present a systematic derivation of perturbed charge density distributions in one-, two-, and three-dimensional systems and establish a conceptual link between FOs, electron delocalization, and the mesomeric effect, using the electron delocalization range function (EDR), offering insights into the reactivity of molecules featuring conjugated bonds. Finally, we propose an effective way to extend the analytical approach native to solid-state physics to describe charge oscillations in cumulenes and polyynes.