First, the electric field experienced by species in solution exhibits broad fluctuations about the mean. Second, unlike the fluctuations in the U α , the width of electric field fluctuations exhibits no significant dependence on system size or system position. These points support the use of Madelung electric fields as a robust and transferable probe of the local electrostatic environment. Figure presents a plot of P (E z ) for Na + and Cl -species in a bulk periodic replicated simulation of a 0.5M aqueous electrolyte solution. In the bulk, the average field is zero, and so the average of any component of the electric field vector is also zero. We observe that the statistics of field fluctuations for Na + and Cl -are similar but not identical. These subtle differences are due to differences in the solvation structure of these two different species. The notable observation from this calculation is that the widths of these distributions indicate a standard deviation of about 0.3V/Å. Evidently, at least in this model of an aqueous electrolyte solution, the strength of fluctuating fields experienced by species in solution can be quite large at any given instance, yet these strong fields persist only fleetingly.