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Re: water microstructure




Here's a quote from "Life's Matrix" by Philip Ball
"The picture of water structure that emerges from computer simulations,
therefore is neither icelike nor like a fully random vapor. The molecules
form a continuous, disordered, and dynamic network of hydrogen bonds in
which each molecule is linked with up to four (or, very rarely, five)
others. Because the hydrogen-bonded network is floppier, more distorted,
and more defective than that in ice, the molecules are able to occupy some
of ice's interstitial space, making the liquid denser than the solid. The
degree of distortion becomes greater as the temperature is raised from the
melting point of 32F, and so the liquid goes on getting denser until it
reaches a maximum density at 39F. Above this temperature, enough hydrogen
bonds have been broken that the liquid starts to behave normally (at least
more normally), becoming less dense with increasing temperature because the
thermal jiggling of the molecules tends to keep their neighbors at an
increasing distance."

Much modeling work is done on this topic at Boston University - by Gene
Stanley.
http://buphy.bu.edu/

Regards-
Larry

Dr. Lawrence D. Woolf; General Atomics, 3550 General Atomics Court, Mail
Stop 15-242, San Diego, CA 92121