Large variation of vacancy formation energies in the surface of crystalline ice

Watkins, Matthew and Pan, D. and Wang, E. G. and Michaelides, A. and VandeVondele, J. and Slater, B. (2011) Large variation of vacancy formation energies in the surface of crystalline ice. Nature Materials, 10 (10). pp. 794-798. ISSN 1476-1122

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Item Type:Article
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Abstract

Resolving the atomic structure of the surface of ice particles within clouds, over the temperature range encountered in the atmosphere and relevant to understanding heterogeneous catalysis on ice, remains an experimental challenge. By using first-principles calculations, we show that the surface of crystalline ice exhibits a remarkable variance in vacancy formation energies, akin to an amorphous material. We find vacancy formation energies as low as �0.1-0.2 eV, which leads to a higher than expected vacancy concentration. Because a vacancy's reactivity correlates with its formation energy, ice particles may be more reactive than previously thought. We also show that vacancies significantly reduce the formation energy of neighbouring vacancies, thus facilitating pitting and contributing to pre-melting and quasi-liquid layer formation. These surface properties arise from proton disorder and the relaxation of geometric constraints, which suggests that other frustrated materials may possess unusual surface characteristics. © 2011 Macmillan Publishers Limited. All rights reserved.

Keywords:Crystalline ice, First-principles calculation, Formation energies, Geometric constraint, Ice particles, Pre-melting, Proton disorder, Quasiliquid layers, Surface characteristics, Temperature range, Vacancy concentration, Vacancy formation energies, Amorphous materials, Calculations, Catalysis, Crystalline materials, Liquids, Surface properties, Surface structure, Vacancies, Ice
Subjects:F Physical Sciences > F200 Materials Science
Divisions:College of Science > School of Mathematics and Physics
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ID Code:17708
Deposited On:19 Aug 2015 14:27

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