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| Titel |
Morphology changes in stacking-disordered ice Ich as a function of time and temperature |
| VerfasserIn |
Werner F. Kuhs, Andrzej Falenty, Thomas C. Hansen |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250110354
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| Publikation (Nr.) |
 EGU/EGU2015-10340.pdf |
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| Zusammenfassung |
| Laboratory experiments have shown that ice I crystallizing from water vapour [1] or
undercooled liquid water [2] under atmospheric conditions initially forms a stacking
disordered arrangement of high complexity; the stacking arrangement is different depending
on the starting phase[1]. Both cubic and hexagonal components are locally present and
various names of this form of ice have been proposed recently: so-called ice Ic or “ice Ic”[1],
ice Isd [2] or ice Ich[3]. It is has been shown that ice Ich undergoes a progressive
transformation of cubic into hexagonal stackings with time and/or increasing temperature [1].
As a mechanisms for this annealing we had proposed the cooperative action of Bjerrrum
defects and moving dislocations which become active on a time-scale of minutes at
temperatures close to 240K [4]. Here we show from electron-microscopic images that the
presence of stacking faults is linked to numerous kinks on the prismatic faces of the
trigonal ice crystals of ice Ich [1]. We present details on the annealing kinetics in the
temperature range between 170 and 240K and suggest that the kinks of ice Ich crystals
may be responsible for the roughness deduced from some air-borne light-scattering
experiments, an increased reactivity in particular at temperatures below ~ 200K as well as
curvature-induced higher vapour pressures of ice Ich as compared to normal ice
Ih.
[1] W.F.Kuhs, C.Sippel, T.C.Hansen (2012) PNAS 109:21259-21264
[2] T.Malkin, B.J.Murray, A.V.Brukhno, J.Anwar, C.G.Salzmann (2012) PNAS 109:
1041-1045
[3] T.C.Hansen, C.Sippel, W.F.Kuhs (2014) Z.Krist. DOI 10.1515/zkri-2014-1780
[4] W.F.Kuhs, G.Genov, D.K.Staykova, T.Hansen (2004) 6:4917-4920 |
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