8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

P2.68Tue 611:23-14:00Is there a riskless way to enter the water’s no-man’sland?Maria-Antonietta Ricci, 1 Fabio Bruni, 1 and Rosaria Mancinelli 11 Universita’ Roma Tre, Dipartimento di Fisica E. Amaldi, via della Vasca Navale 84 00146,Roma, ItalyThe well known anomalies shown in several response functions of water when its supercooledregime is entered can be explained by its thermodynamic behaviour in the so-called no-man’sland: a region of the thermodynamic space, where experiments in pure liquid water are notfeasible. Theoreticians are debating in the literature about the possible existence of a secondcritical point [1], ending the coexistence line between two polymorphs water, namely high densityand low density water, while experimentalists are trying to enter the no-man’s land by using”tricks” or approximations. The most popular tricks are solvation of salts [2], or confinement ofwater in small enough volumes [3]. In both cases data interpretation requires careful account ofthe water - substrate/solute interaction [4]. We will discuss the merit and limits of this approachto the no man’s land, through the analysis of neutron diffraction data. New dielectric relaxationmeasurements, performed on confined water will be interpreted in the light of the structuralfindings.[1] H. E. Stanley, et al. , PCCP 2, 1551E1558 (2000).[2] Handbook of Chemistry and Physics. CRC Press.[3] F. Mallamace, et al. , PNAS USA, 104, 424 (2007); F. Mallamace, et al. , PNAS. USA, 104,18387 (2007).[4] R. Mancinelli et al. , JPC Lett. 1, 1277 (2010); A. Botti, et al. , JCP 120, 10154 (2004); R.Mancinelli, et al. , PCCP 9, 2959 (2007); R. Mancinelli, et al. , JPC B 111, 13570 (2007); J.Holzmann, et al. , Angew. Chem. , Int. Ed. 46, 8907 (2007).68