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The Static Dielectric Constant of Liquid Water Between 274 and 418 K Near the Saturated Vapor Pressure

Published

Author(s)

J O. Hamelin, J B. Mehl, Michael R. Moldover

Abstract

The complex dielectric constant (relative electric permittivity) [epsilon]r = [epsilon]' - I[epsilon]'' of liquid water was redetermined in the temperature range 0 Cr was deduced from measurements of the resonant frequencies falpha] of a novel, re-entrant, two-mode, radio-frequency resonator. The frequencies ranged from 23 MHz to 84 MHz and were well within the low-frequency limit for [epsilon]' because (2πfα Tmax)2-5 where Tmax) = 1.8 x 10-11 s is the s is the maximum relaxation time of water under the conditions studied. The data for t{epsilion}' for two water samples differing in conductivity by a factor of 3.6 and the two resonant mdoes differing in frequency by a factor of 2.6 were simulaneously fit by the polynomial function {epsilion}'(I) = 87.9144 - 0.404399/ + 9.58726 x 10-4/2 - 1.32802 x 10 -6/3 with a remarkably small residual standard deviation of 0.005. The present data are consisient with previously published data: however, they are more precise and internally consistent. The present apparatus was also tested with cyclohexane and yielded the values {epsilion}'(t) = 2.0551 - 0.00156/ for 20 C 2 where Tmax = 1.8x10-11 s is the maximum relaxation time of water under the conditions studied. The data for [epsilon]' for two water samples differing in conductivity by a factor of 3.6 and for the two resonant modes differing in frequency by a factor of 2.6 were simultaneously fit by the polynomial function [epsilon]'(t) = 87.9144 - 0.404399 t + 9.58726x10-4t2 - 1.320802x10-6t3 with a remarkably small residual standard deviation of 0.0055. The present data are consistent with previously published data; however, they are more precise and internally consistent. The present apparatus was also tested with cyclohexane and yielded the values [epsilon]'(t) = 2.0551 - 0.00156 t for 20 C
Citation
International Journal of Thermophysics
Volume
19
Issue
No. 5

Keywords

cyclohexane, dielectric constant, reentrant radio-frequency resonator, relative permittivity, static dielectric constant, water
Created January 1, 1998, Updated February 17, 2017