[3dem] Alasdair and vitreous water.

[Sue Tivol]

> On Jun 14, 2019, at 1:18 PM, Jacques Dubochet <jacques at dubochet.ch> wrote:
> 
> The present work by Tulk at all. (2019) (also read the explanation by J.S.Tse (2019)) is for me a big relief. What they did is simple, in principle; they just took time ! Along the line initiated by Mishima, they compressed ice I at 100 K but they did it in incremental steps, waiting an hour at each step. No HDA was formed under these conditions but, with increasing pressure, the material was transformed into different forms of crystalline ice. Confirming previous results, HDA was produced when the pressure was increased without pausing. They conclude that HDA is the kinetically arrested transformation between ice I and some forms of high density ice crystals; it is not a thermodynamically defined state.
> 
> 
Hi Jacques,
	At the Jensen Lab in 2006 we looked into ice structure at a sufficiently low temperature that HDA formed in the microscope upon electron irradiation.  Also, in the book, Physics of Ice, it was stated that HDA is the most stable form at the lowest temperatures—another interesting anomaly of water, that its 0 K form is not crystalline.  In one of the references of the paper cited below, it is stated that HDA is by far the most common form of water in the known universe.
						Yours,
						Bill


 Wright, E. R., Iancu, C. V., Tivol, W. F., and Jensen, G. J., Observations on the Behavior of Vitreous Ice at ~82 and ~12 K. Journal of Structural Biology, (2006) 153, 241-252.

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