Impedance of the free surface of liquid electrolytes
  A possibility for the observation of so-called structure resonances (SR) in electrolytes arising due to relative motion of the cluster charged nucleus and its solvation shell is demonstrated. The discussed method considers the resonant contribution of the SR to the frequency dependence of the reflection (transmission) coefficient of the electromagnetic wave interacting with the free electrolyte surface. Of special interest is the observation of SR for multiply charged particles in electrolyte providing direct information on the charge of single cluster. Also important are other not so prominent details of the wave interaction with mobile charged clusters in electrolyte related to the formation and complicated nature of the frequency dependence of the charged cluster associated mass. 
V. Dashkovsky and I. Chikina
cond-mat.soft