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

Tue 611:23-14:00P2.17Equation of state of water measured down to -260 barsKristina Davitt, 1 Etienne Rolley, 1 Frederic Caupin, 2 Arnaud Arvengas, 1 andSebastien Balibar 11 Laboratoire de Physique Statistique, Ecole Normale Superieure, 24, rue Lhomond 75005,Paris, France2 Laboratoire de Physique de la Matiere Condensee et Nanostructures, Villeurbanne,FranceThere is no consensus on the equation of state of water; this is particularly true for metastablestates such as stretched water. Indeed, the most extensive PVT measurements of water undertension were made a century ago [1] and reached only -34 bars. We have developed all-opticalmethods to perform time-resolved measurements of the speed of sound and the density as theliquid is alternately stretched and compressed by the passage of an ultrasonic wave. Combiningresults obtained from Brillouin-scattering and from a fiber optic hydrophone, we have investigatedthe behaviour of water down to -260 bars [2]. The new thermodynamic data support the validity ofextrapolating current empirical equations of state to negative pressures and provides a constraintfor any newly proposed models of water. Furthermore, it allows us to comment on the diversity ofexperimental measurements that have been reported for the cavitation threshold - or the limitingtension - which range from -300 to -1400 bars.[1] J. Meyer, Abhandl. d. Deutsch Bunsen-Gessellschaft 6 1, (1911).[2] K. Davitt et al., J. Chem. Phys. 133 17, 174507 (2010).17