Microscopic formulation of non-local electrostatics in polar liquids embedding polarizable ions

Tutkimustuotos: Lehtiartikkelivertaisarvioitu

Tutkijat

Organisaatiot

Kuvaus

Nonlocal electrostatic interactions associated with finite solvent size and ion polarizability are investigated within the mean-field linear response theory. To this end, we introduce a field-theoretic model of a polar liquid composed of linear multipole solvent molecules and embedding polarizable ions modeled as Drude oscillators. Unlike previous dipolar Poisson-Boltzmann formulations treating the solvent molecules as point dipoles, our model is able to qualitatively reproduce the non-local dielectric response behavior of polar liquids observed in molecular dynamics simulations and atomic force microscope experiments for water solvent at charged interfaces. The present theory explains the formation of the associated interfacial hydration layers in terms of a cooperative dipolar response mechanism driven by the reaction of the solvent molecules to their own polarization field. We also incorporate into the theory the relative multipole moments of water molecules obtained from quantum mechanical calculations and show that the multipolar contributions to the dielectric permittivity are largely dominated by the dipolar one. We find that this stems from the mutual cancellation of the first two interfacial hydration layers of opposite net charge for multipolar liquids. Within the same nonlocal dielectric response theory, we show that the induced ion polarizability reverses the interfacial ion density trends predicted by the Poisson-Boltzmann theory, resulting in a surface affinity of coions and exclusion of counterions. The results indicate that the consideration of the discrete charge composition of solvent molecules and ions is the key step towards a microscopic understanding of nonlocal electrostatic effects in polar solvents.

Yksityiskohdat

AlkuperäiskieliEnglanti
Artikkeli063201
Sivut1-14
JulkaisuPhysical Review E
Vuosikerta87
Numero6
TilaJulkaistu - 2013
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

    Tutkimusalat

  • Polar liquid, non-local electrostatics, ion polarizability

ID: 822194