Tuesday, March 12, 2019

intermolecular forces - Does water really have strong EM absorption at 3 kHz in solid and 2 GHz in liquid? Why the huge shift?


While writing this answer to the question Transmitter receiver coil separation for Electromagnetic Terrain Conductivity Measurement I ran across this large PDF file of a book Soil and Environmental Analysis; Physical Methods Soil and Environmental Analysis; Physical Methods, 2nd Ed. K. A. Smith and C. E. Mulllins, Eds. 2000 Dekker, New York.


Figure 5. on page 29 is shown below. It shows a plot of the real and imaginary part of the permittivity of water in solid (ice) and liquid forms.


The shapes are the roughly the same; the real part is around 80 to 90 at low frequency and drops to perhaps 2 to 1 at high frequency, with the imaginary part reaching a peak as the slope of the real part is maximum as one would expect.


The difference however is that the peak in the absorption is around 3 kHz for ice and 20 GHz for liquid!




  1. Is the physics behind this strong absorption peak the same in both cases?

  2. If so, what is it about the transition from solid to liquid that can move it seven orders of magnitude?


enter image description here




No comments:

Post a Comment

digital communications - Understanding the Matched Filter

I have a question about matched filtering. Does the matched filter maximise the SNR at the moment of decision only? As far as I understand, ...