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Ice XI: The ordered form of ICE Ih

Howe, Rachel (1988)
Ph.D. thesis, University of Birmingham.

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Abstract

The history of the development of the understanding of the statistical arrangement of hydrogen bonds in ice Ih and the discovery of the transition at 72 K to the ordered phase, ice XI, catalysed by alkali hydroxide doping, is reviewed. Possible ordered arrangements of hydrogen bonds are discussed and enumerated. A theory is presented relating the entropy and permittivity of partially ordered ice to the degree of order. The apparatus developed for dielectric experiments on KOH-doped ice is described. The results of such measurements for polycrystalline specimens and one single crystal are presented. Measurements above the transition reveal that the main charge carriers are OH\(^-\) ions, with a temperature-independent mobility of approximately 10\(^-\)\(^1\)\(^0\) m\(^2\) v\(^-\)\(^1\) s\(^-\)\(^1\). The transformation to the ordered phase starts when the sample is cooled below about 65 K, and once started can be speeded up by heating the sample to 67-70 K: the static permittivity and the a.c. conductivity slowly decrease. Neutron powder diffraction experiments were performed on HRDP at ISIS. After one unsuccessful experiment, dielectric measurements on powder samples showed the importance of excluding CO\(_2\) during preparation. In a second experiment the structure of ice XI was confirmed and the lattice parameters determined for the first time.

Type of Work:Ph.D. thesis.
Supervisor(s):Whitworth, R.W
School/Faculty:Faculties (to 1997) > Faculty of Science
Department:School of Physics and Space Research
Keywords:Ice, Ice XI, neutron diffraction, phase transition, dielectric properties, partial order
Subjects:QC Physics
QD Chemistry
Institution:University of Birmingham
ID Code:5255
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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