title: Charge fluctuations in nanoscale capacitors.
abstract: The fluctuations of the charge on an electrode contain information on the microscopic correlations within the adjacent fluid and their effect on the electronic properties of the interface. We investigate these fluctuations using molecular dynamics simulations in a constant-potential ensemble with histogram reweighting techniques. This approach offers, in particular, an efficient, accurate, and physically insightful route to the differential capacitance that is broadly applicable. We demonstrate these methods with three different capacitors: pure water between platinum electrodes and a pure as well as a solvent-based organic electrolyte each between graphite electrodes. The total charge distributions with the pure solvent and solvent-based electrolytes are remarkably Gaussian, while in the pure ionic liquid the total charge distribution displays distinct non-Gaussian features, suggesting significant potential-driven changes in the organization of the interfacial fluid.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: David T
authors.initials: DT
authors.lastname: Limmer
authors.affiliation: UPMC Univ-Paris 06 and CNRS, UMR 7195, PECSA, F-75005, Paris, France and Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, France.
authors.forename: Céline
authors.initials: C
authors.lastname: Merlet
authors.affiliation: UPMC Univ-Paris 06 and CNRS, UMR 7195, PECSA, F-75005, Paris, France and Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, France.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Salanne
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: David
authors.initials: D
authors.lastname: Chandler
authors.affiliation: Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, United Kingdom.
authors.forename: Paul A
authors.initials: PA
authors.lastname: Madden
authors.affiliation: Institute for Theoretical Physics, Utrecht University, 3584 CE Utrecht, The Netherlands.
authors.forename: René
authors.initials: R
authors.lastname: van Roij
authors.affiliation: UPMC Univ-Paris 06 and CNRS, UMR 7195, PECSA, F-75005, Paris, France and Réseau sur le Stockage Electrochimique de l'Energie (RS2E), FR CNRS 3459, France.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Rotenberg