Programme

P.22 -- Poster, NCTP-43

Date: Tuesday, 31 July 2018

Time: 08:30 - 10:00

Dielectric constant of sodium chloride solution below terahertz frequency

Tran Thi Nhan (1) and Le Tuan (2)

(1) Hanoi University of Industry, 298-Cau Dien Road, Hanoi; (2) Hanoi University of Science and Technology, 1-Dai Co Viet Road, Hanoi

The dispersion of permittivity of the salt solution with different concentrations below the microwave frequency is represented via the modified relaxation Debye model in which the relaxations related to the rotation of free water molecules, ion-dipole polarization of hydrated ions, and translation of free ions are examined. This model is reasonable to describe the relaxation of the dielectric constant for the salt solution with low concentration at two Debye relaxation frequencies: the lower one relates to the ion-dipole relaxation and the higher one corresponds to the rotational relaxation of free water molecules. In addition, the increase in ion-dipole Debye frequency with the increase in the salt concentration is explained. The model also shows that the salt solution comprises about only 10.5 % free ions which are responsible for the conductivity of the solution. To the salt solution with medium concentration, the complex permittivity is modeled as a sum of the Debye relaxation term of the free water molecules with the part contributed from free ions without the relaxation part related to hydrated ions. In this situation, free ions behavior as free electrons in crystal. For that reason, some parameters of free ions such as average speed, mean free path, mobility are estimated via the Drude's classical theory. This model could be useful to study similar electrolyte solutions.

Presenter: Tran Thi Nhan