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Proton Ordering of Cubic Ice Ic

Autor(en)
Philipp Geiger, Christoph Dellago, Markus Macher, Cesare Franchini, Georg Kresse, Juergen Bernard, Josef N. Stern, Thomas Loerting
Abstrakt

Several proton-disordered crystalline ice structures are known to proton order at sufficiently low temperatures, provided that the right preparation procedure is used. For cubic ice, ice Ic, however, no proton ordering has been observed so far. Here, we subject ice Ic to an experimental protocol similar to that used to proton order hexagonal ice. In situ FT-IR spectroscopy carried out during this procedure reveals that the librational band of the spectrum narrows and acquires a structure that is observed neither in proton-disordered ice Ic nor in ice XI, the proton-ordered variant of hexagonal ice. On the basis of vibrational spectra computed for ice Ic and four of its proton-ordered variants using classical molecular dynamics and ab initio simulations, we conclude that the features of our experimental spectra are due to partial proton ordering, providing the first evidence of proton ordering in cubic ice. We further find that the proton-ordered structure with the lowest energy is ferroelectric, while the structure with the second lowest energy is weakly ferroelectric. Both structures fit the experimental spectral similarly well such that no unique assignment of proton order is possible based on our results.

Organisation(en)
Computergestützte Physik und Physik der Weichen Materie, Institut für Lehrer*innenbildung, Computergestützte Materialphysik
Externe Organisation(en)
Leopold-Franzens-Universität Innsbruck, Universität Wien
Journal
The Journal of Physical Chemistry Part C (Nanomaterials and Interfaces)
Band
118
Seiten
10989-10997
Anzahl der Seiten
9
ISSN
1932-7447
DOI
https://doi.org/10.1021/jp500324x
Publikationsdatum
05-2014
Peer-reviewed
Ja
ÖFOS 2012
103009 Festkörperphysik, 103015 Kondensierte Materie, 103025 Quantenmechanik, 103036 Theoretische Physik
Schlagwörter
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/e728faf3-33a5-42c2-97bf-2d2e7454e2f9