Regensburg 2013 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 17: Glasses II (joint session DY/DF/CPP)

CPP 17.2: Talk

Tuesday, March 12, 2013, 09:45–10:00, H46

On the behavior of supercooled liquid water in Confinements formed by frozen water molecules: a molecular dynamics simulation study — •Felix Klameth and Michael Vogel — Institut für Festkörperphysik, TU Darmstadt, 64289 Darmstadt

Molecular dynamics simulations are performed to study the influence of an amorphous ice confinement on liquid water. Investigating water in confinement is believed to reveal information unaccessible for bulk water due to crystallization. Therefore, there are numerous studies on confined water, which claim, e.g., existence of a second critical point associated with a liquid-liquid phase transition in the supercooled regime [1]. However, transfer of information from confined water to bulk water is not straightforward because introducing walls changes the static properties of water due to specific interactions at the interfaces. To avoid this drawback, we use a neutral confinement comprised of immobilized water molecules. We compare static and dynamical properties found in pores with different radii to that of bulk water. The static characteristics, like the tetragonal order parameter, are not changed even near the pore wall. On the contrary, the dynamics inside the pore are dramatically influenced. We find a tremendous increase of the structural relaxation time of liquid water when approaching the pore wall. Thus, we observe a strong change of the local dynamics, which is neither accompanied by a variation of the local structure nor caused by specific wall-liquid interactions. Possible origins for this effect are discussed. [1] P. Kumar et al, PRL (2006), 97, 177802