Microscopic approach for low-frequency dielectric constant of liquid water

ABSTRACT

A theoretical model has been proposed for interpreting the dispersion of the low-frequency dielectric constant of liquid water with two separate arguments. The first argument relates to dipole orientation in the water system and the second one concerns motions of ions towards the electrodes. It reveals that the compensation between these two arguments leads to the isopermittive point, at which the water dielectric constant holds constant in the range of temperature from 301 K to 313 K. The existence of the isopermittive point is also highlighted under the view from the basis of thermodynamics. We show that the isopermittive point only exists in a narrow region of temperature. The changes in enthalpy and Gibbs free energy are estimated, using van’t Hoff equation, for the water system in the equilibrium. Our theoretical model can help in the perspective research on dynamic processes happening in live cells around the crossing point.

KEYWORDS:

• Simple mode
• water dielectric constant
• low frequency
• isopermittivity point
• van’t Hoff equation

Acknowledgements

We acknowledge Professor Nguyen Ai Viet, Institute of Physics - Vietnam Academy of Science and Technology, for his discussions and support this work.

Disclosure statement

No potential conflict of interest was reported by the authors.