Ion fluctuations within an aqueous microdroplet in an apolar medium
Journal
Physical Review Letters
Journal Volume
87
Journal Issue
18
Pages
185501-1-185501-4
Date Issued
2001-01-01
Author(s)
Tsao, Heng Kwong
Abstract
The density fluctuation of counterions within an aqueous droplet is investigated. In terms of mean-square dipole moment, the fluctuation grows and becomes saturated as the counterion concentration is increased. Using fluctuation-dissipation theorem, the mean-square dipole moment is found to be proportional to the polarizability of the microdroplet. This relation is confirmed by simulations and indicates that the nature of ion fluctuations is possible to be captured by the simple mean-field theory. With the Debye-Hückel approximation, an analytical expression for the mean-square dipole moment is obtained by the Poisson-Boltzmann theory. It agrees reasonably well with the results by simulations. © 2001 American Physical Society.
Publisher
AMER PHYSICAL SOC
Type
journal article