Diffusion in supercooled water to 300 MPa.

Measurements of the self-diffusion coefficient in supercooled ~ater to 300 MPa are reported. Translational diffusion in liquid water at 243 K is enhanced by 60% when the pressure is increased from 0. 1 to 150 MPa, and rotational diffusion is enhanced by almost 250% between 0. 1 and 250 MPa. These striking anomalies are interpreted in terms of the proximity of a conjectured line of spinodal-like stability limits in the supercooled liquid.