Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 35: Poster Session II (Polymeric biomolecular films; Nanostructures; Electronic structure; Spin-orbit interaction; Phase transitions; Surface chemical reactions; Heterogeneous catalysis; Particles and clusters; Surface magnetism; Electron and spin dynamics; Surface dynamics; Methods; Electronic structure theory; Functional molecules)

O 35.46: Poster

Dienstag, 27. März 2012, 18:15–21:45, Poster B

Atomistic Simulations of Pressure-Induced Structural Transformations in Ice Nanocrystals — •Konstantin Weber^{1, 2} and Carla Molteni¹ — ¹King’s College, Physics Department, London, UK — ²ICMM/CCC, University of Erlangen-Nürnberg, Germany

Ice has a very complex and widely studied phase diagram, which includes many crystalline phases (stable as, e.g., ice Ih, ice II, and ice III, and metastable ones as ice Ic) as well as amorphous phases. Pressure can be used to induce structural transitions between these phases, allowing the study of transition mechanisms and of phase dependent properties. Ice nanocrystals of variable size add an extra dimension to the phase diagram, and it is interesting to understand how size affects the phase transformations. We present the results of a series of simulations where we have modeled pressure-induced structural transformations in ice Ih nanocrystals using the classical TIP4P force field, a constant pressure molecular dynamics method for finite systems, and the metadynamics technique for accelerating rare events. Metadynamics allows us to study the phase transformations at realistic pressure conditions, without the need to overpressurize the systems as in conventional molecular dynamics because of time scale limitations.