dielctric constant of water near the freezing point (fwd)

• To: Water Science Network <water@gibbs.oit.unc.edu>
• Subject: dielctric constant of water near the freezing point (fwd)
• From: Water Science Network Administrator <wsn-adm@mmlds1.pha.unc.edu>
• Date: Mon, 25 Apr 1994 10:17:17 -0400 (EDT)

Sender: anneke@tiber.nist.gov (J M H L Sengers)
Subject: WSN: dielctric constant of water near the freezing point


The dielectric constant of water rises steeply as the temperature falls
below the temperature of maximum density (even though the density is then
decreasing). The dielectric constant keeps rising into the supercooled regime.
See, for instance, Bertolini et al., J. Chem. Phys. 76, 3285 (1982).

I do not know anything about the dielectric constant of ice.

It is quite difficult to accurately measure the dielectric constant
of water, since about any method you use will be quite sensitive
to the conductivity of the water sample. We just finished some
new measurments at NIST in the range of the freezing point to the boiling
point. Our water had a conductivity no more than 30% over the theoretical
limit, and we could demonstrate a dependence of the apparent, measured 
dielectric constant, if the water sample was less pure. I shudder to
think what may happen if one sticks a sensor into wet soil.

Think also what may happen if part of your sample freezes. The impurities will
be forced out into the liquid water.

For a recent correlation of the dielectric constant of water, see
Archer and Wang, J.Phys. Chem. Ref. Data 19, 371, 1990.

Johanna M.H. (Anneke) Levelt Sengers
Thermophysics Division 
NIST

• Prev: Guanidine Hydrochloride solution (fwd)
• Next: WSN: Conference on Membrane Molecular Biophysics (reposted)
• Index: Mail Index
• Thread: Mail Thread Index