Frequency dependence of the ionic conductivity in water + ammonium nitrate electrolyte solutions

• Frequency dependence of the electrical conductivity in water + NH4NO3 electrolyte solutions has been investigated.
• It was found that the relaxation spectra related to the double layers formation can be described with a large distribution of the relaxation times and the relaxation due to the ions inertia – with a single relaxation time.
• It was found that with increasing of the conductivity of solutions the double layers relaxation proceeds faster and the relaxation related to the ions inertia proceeds slower.

ABSTRACTTwo ionic relaxation processes reveal in the conductivity spectra recorded for the electrolyte solutions of water + NH4NO3. In the kilohertz range of the frequency of electric stimulus one observes the relaxation related to the double layers formation at the blocking electrodes/electrolyte interface and in the megahertz range – the relaxation due to the ions inertia. The low frequency process exhibits a large distribution of the relaxation times and can be well described with an empirical Cole-Cole – type equation while the high frequency process is exactly of the Debye-type, as predicted by the theory of Chandra and Bagchi. It was found an inverse dynamic behavior of these two processes in relation to the conductivity level: the higher conductivity the faster double layers relaxation and the slower relaxation related to the ions inertia.

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