Electronic resonances on a metal surface associated with adsorption

Physical aspects of the nature of chemical bonding of halogenide anions with the surface of a metal electrode during specific adsorption from electrolyte solution were considered on a qualitative level. It was shown that a description of a typical dissipative quantum system (adsorbate-substrate) can be approximated by the one-electron mechanism of bonding, allowing stationary fractional separation of the electron charge density between the atomic core of the anion and metal. Partial charge transfer from anion to metal is due to the tunneling permeability of potential barrier separating the quasi-stationary state of valent electron in the anion from free electron states in the metal. The local volume density of this charge is formed as a result of potential scattering of electron waves of metal on an anion atomic core and is concentrated near the inner surface in the vicinity of the scattering center. The residual charge of the adsorbed anion is supported by resonant scattering on the atomic core of electron waves of occupied electron states of the metal from the vicinity of the Fermi boundary. Conservation of the total charge is guaranteed by the Friedel sum rule. A physical model was used to interpret the patterns observed in the data of electrosorption valency measurements.