We made a molecular dynamics study of single-particle dynamics of water molecules in deeply supercooled liquid states. We find that the time evolution of various single-particle time correlation functions is characterized by a fast initial relaxation toward a plateau region, where it shows a self-similar dynamics, then followed by a slow, stretched exponential decay to zero at much later times. We interpret these results in the frame-work of a mode-coupling theory for supercooled liquids. We relate the apparent anomalies of transport coefficients in this model water, on lowering the temperature, to the formation of a long-lived cage around each water molecule and the associated slow dynamics of the cages. The experimentally observed so-called Angell temperature, which is an apparent limit of supercooling in liquid water, could thus be interpreted as a kinetic glass transition temperature predicted by the mode-coupling theory. We then discuss to what extent the experimental incoherent quasi-elastic neutron scattering data from supercooled bulk water support the idea of the existence of the slow dynamics.

Chen, S.h., Gallo, P., Sciortino, F., & Tartaglia, P. (1997). Slow dynamics in a model and real supercooled water. In J. T. Fourkas (a cura di), Supercooled liquids : advances and nove applications (pp. 264-286).

Slow dynamics in a model and real supercooled water

GALLO, PAOLA;
1997

Abstract

We made a molecular dynamics study of single-particle dynamics of water molecules in deeply supercooled liquid states. We find that the time evolution of various single-particle time correlation functions is characterized by a fast initial relaxation toward a plateau region, where it shows a self-similar dynamics, then followed by a slow, stretched exponential decay to zero at much later times. We interpret these results in the frame-work of a mode-coupling theory for supercooled liquids. We relate the apparent anomalies of transport coefficients in this model water, on lowering the temperature, to the formation of a long-lived cage around each water molecule and the associated slow dynamics of the cages. The experimentally observed so-called Angell temperature, which is an apparent limit of supercooling in liquid water, could thus be interpreted as a kinetic glass transition temperature predicted by the mode-coupling theory. We then discuss to what extent the experimental incoherent quasi-elastic neutron scattering data from supercooled bulk water support the idea of the existence of the slow dynamics.
Chen, S.h., Gallo, P., Sciortino, F., & Tartaglia, P. (1997). Slow dynamics in a model and real supercooled water. In J. T. Fourkas (a cura di), Supercooled liquids : advances and nove applications (pp. 264-286).
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11590/133126
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