ELASTIC PROPERTIES OF WATER UNDER NEGATIVE PRESSURES

Using Brillouin scattering we have investigated the elastic properties of water under negative pressures. The samples were H2O liquid-vapor inclusions in alpha-quartz which could be heated to their homogenizati on temperatures (in the range 120-370-degrees-C); on cooling, negative pressures as high as 1000 bars were reached before a vapor bubble nuc leated. The velocity of sound results obtained from our Brillouin expe riments indicate that nucleation occurs long before reaching the mecha nical instability region where the bulk modulus is zero.