Ions confined in spherical dielectric cavities modeled by a splitting fieldtheory.
Forskningsoutput: Tidskriftsbidrag › Artikel i vetenskaplig tidskrift
Abstract
The properties of ions confined within spherical dielectric cavities are examined by a splitting fieldtheory and Monte Carlo simulations. Three types of cavities are considered: one possessing a uniform surface charge density, one with a uniform volume charge density, and one containing mobile ions. In all cases, mobile counterions are present within the dielectric sphere. The splitting theory is based on dividing the electrostatic interaction into long and shortwavelength contributions and applying different approximations on the two contributions. The splitting theory works well for the case where the dielectric constant of the confining sphere is equal to or less than that of the medium external to the sphere. Nevertheless, by extending the theory with a virial expansion, the predictions are improved. However, when the dielectric constant of the confining sphere is greater than that of the medium outside the sphere, the splitting theory performs poorly, only qualitatively agreeing with the simulation data. In this case, the strongcoupling expansion does not seem to work well, and a modified meanfield theory where the counterions interact directly with only their own image charge gives improved predictions. The splitting theory works best for the system with a uniform surface charge density and worst for the system with a uniform volume charge density. Increasing the number of ions within the sphere, at a fixed radius, tends to increase the ion density near the surface of the sphere and leads to a depletion region in the sphere interior; however, varying the ion number does not lead to any qualitative changes in the performance of the splitting theory.
Detaljer
Författare  

Enheter & grupper  
Forskningsområden  Ämnesklassifikation (UKÄ) – OBLIGATORISK

Originalspråk  engelska 

Artikelnummer  144902 
Tidskrift  Journal of Chemical Physics 
Volym  142 
Utgivningsnummer  14 
Status  Published  2015 
Publikationskategori  Forskning 
Peer review utförd  Ja 