Archive 2017

Here you can find past events of the MPSD institute.

Room: Seminar Room I-II, EG.076-078 Host: R. J. Dwayne Miller

Shinji Saito - Supercooled water: Fluctuation, glass transition, and vibrational entropy

MPSD ARD Seminar
Water is the most common liquid. Its properties are not, however, common. Since the anomalies of water become pronounced at low temperatures, especially below its melting temperature, it has been proposed that the anomalous properties are attributed to the presence of two liquid states corresponding to the two amorphous ices. Experimental studies of supercooled water are however very difficult. This is due to the fact that bulk water is easily transferred to a crystalline phase in the “no man’s land”, which is a temperature range bounded by the crystallization of supercooled water at ~235K and by that of highly viscous liquid water at ~150K. Therefore, various theoretical and computational studies have been conducted for understanding the properties in the no man’s land. We have performed extensive molecular dynamics simulations from normal liquid to deeply supercooled states to reveal the structural and dynamical instabilities in the no man’s land. The spatiotemporal fluctuations, dynamic transition, glass transition, and vibrational contribution to Kauzmann temperature of supercooled water will be discussed. [more]
Spectroscopic mapping by STEM/EELS has proven to be a powerful technique for determining the structure, chemistry and bonding of interfaces, reconstructions, and defects. So far, most efforts in the physical sciences have focused on room temperature measurements where atomic resolution mapping of composition and bonding has been demonstrated [1-3]. For many materials, including those that exhibit electronic and structural phase transitions below room temperature and systems that involve liquid/solid interfaces, STEM/EELS measurements at low temperature are required. Operating close to liquid nitrogen temperature gives access to a range of emergent electronic states in solid materials and allows us to study processes at liquid/solid interfaces immobilized by rapid freezing [4,5]. [more]
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