Seminaire de Matiere Condensee et Physique Statistique: Water and Anomalous Liquids

by Prof. Giancarlo Franzese (Univ. de Barcelone)

Friday 14 Nov 2008, 14:00 → 15:00 Europe/Zurich

EPFL, Salle 727 du BSP

Water is an essential fluid for the life, although its behavior often diverges from that of what could be considered a “normal” fluid. In fact, presently there are at least sixty known anomalies of water. One of them, for example, is related to the increase of density with temperature, which allows the fishes to survive beneath frozen lakes. Another example would be the high capacity to absorb heat, an essential fact for the regulation of our body temperature. Another peculiar fact is that liquid water can reach, without freezing, extremely low temperatures: -47 ºC in a plant and -92ºC in a laboratory. Under 0 ºC it has been observed that liquid water displays two configurations with different densities. Nevertheless, it has still not been possible to determine if these configurations can be considered as two different phases, like the liquid and the gas. In order to explain these phenomena, several hypotheses have been proposed. They display the same theoretical predictions in the region accessible to the experiments, but they have different implications and, until now, none of them has been ruled out by the experiments. In this talk I will discuss their implications in different systems, such as proteins solutions, and how water is related to other anomalous liquids, such as liquid metals.