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dc.contributor.authorAnwar, Jamshed*
dc.contributor.authorDavidchack, R.*
dc.contributor.authorHandel, R.*
dc.contributor.authorBrukhno, Andrey V.*
dc.date.accessioned2011-01-27T15:56:50Z
dc.date.available2011-01-27T15:56:50Z
dc.date.issued2008
dc.identifier.citationAnwar, J., Davidchack, R., Brukhno, A.V. and Handel, R. (2008). Challenges in molecular simulation of homogeneous ice nucleation. Journal of Physics: Condensed Matter. Vol. 20, No. 49.en_US
dc.identifier.urihttp://hdl.handle.net/10454/4757
dc.descriptionNoen_US
dc.description.abstractWe address the problem of recognition and growth of ice nuclei in simulation of supercooled bulk water. Bond orientation order parameters based on the spherical harmonics analysis are shown to be ineffective when applied to ice nucleation. Here we present an alternative method which robustly differentiates between hexagonal and cubic ice forms. The method is based on accumulation of the maximum projection of bond orientations onto a set of predetermined vectors, where different terms can contribute with opposite signs with the result that the irrelevant or incompatible molecular arrangements are damped out. We also introduce an effective cluster size by assigning a quality weight to each molecule in an ice-like cluster. We employ our cluster analysis in Monte Carlo simulation of homogeneous ice formation. Replica-exchange umbrella sampling is used for biasing the growth of the largest cluster and calculating the associated free energy barrier. Our results suggest that the ice formation can be seen as a two-stage process. Initially, short tetrahedrally arranged threads and rings are present; these become correlated and form a diffuse ice-genic network. Later, hydrogen bond arrangements within the amorphous ice-like structure gradually settle down and simultaneously `tune-up¿ nearby water molecules. As a result, a well-shaped ice core emerges and spreads throughout the system. The process is very slow and diverse owing to the rough energetic landscape and sluggish molecular motion in supercooled water, while large configurational fluctuations are needed for crystallization to occur. In the small systems studied so far the highly cooperative molecular rearrangements eventually lead to a relatively fast percolation of the forming ice structure through the periodic boundaries, which inevitably affects the simulation results.en_US
dc.description.sponsorshipEPSRCen_US
dc.relation.isreferencedbyhttp://dx.doi.org/10.1088/0953-8984/20/49/494243en_US
dc.subjectIce freezing; Ice nucleationen_US
dc.subjectmolecular dynamics simulationen_US
dc.subjectIce phases Ih and Icen_US
dc.subjectSpherical harmonics; order parametersen_US
dc.titleChallenges in molecular simulation of homogeneous ice nucleationen_US
dc.status.refereedYesen_US
dc.typeArticleen_US
dc.identifier.JournalTitleJournal of Physics: Condensed Matter 20, 494243 (20 pages), 2008en_US
dc.type.versionNo full-text available in the repositoryen_US


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