title: X-ray reflectivity at polarized liquid-Hg-aqueous-electrolyte interface: challenging macroscopic approaches for ion-specificity issues.
abstract: We report Angstrom-resolved x-ray reflectivity analysis of externally polarized liquid-Hg surface in contact with molar LiCl, LiBr, and MgSO4 aqueous electrolytes. Interpretation of reflectivity curves demonstrates a dependence of Hg-surface layering on both applied potential and ion nature. It further highlights how interfacial polarization degree impacts electron density profiles at a molecular scale. These profiles indicate accumulation of anions and cations at the Hg surface. Upon decrease of the potential from the point of zero charge, anions are gradually expelled from the Hg surface. The study challenges traditional thermodynamic approaches for deriving countercharge composition at the Hg-electrolyte-solution interface from macroscopic Hg-surface tension data. It further dismisses the long-standing approximation that assimilates the Hg surface to a smooth, perfect chemically inert conductor with a uniformly smeared-out surface charge density.
authors.affiliation: Laboratoire Environnement et Minéralurgie, Université de Lorraine, CNRS-INPL UMR 7569, B.P. 40, 54501 Vandoeuvre Cedex, France. jerome.duval@univ-lorraine.fr
authors.forename: Jérôme F L
authors.initials: JF
authors.lastname: Duval
authors.forename: Sambhunath
authors.initials: S
authors.lastname: Bera
authors.forename: Laurent J
authors.initials: LJ
authors.lastname: Michot
authors.forename: Jean
authors.initials: J
authors.lastname: Daillant
authors.forename: Luc
authors.initials: L
authors.lastname: Belloni
authors.forename: Oleg
authors.initials: O
authors.lastname: Konovalov
authors.forename: Diego
authors.initials: D
authors.lastname: Pontoni