Viscosity is one of the most fundamental transport properties in liquid. Recent HPCAT development of high-speed x-ray radiography combined with a Paris-Edinburgh cell enabled viscosity measurements of low viscos (<1 mPa s) liquids and fluids. A falling sphere technique revealed an anomaly in the viscosity of liquid KCl at around 2 GPa. Structural data of liquid KCl showed a pronounced change signified by the ratio r2/r1, where r1 and r2 are the nearest- and the second-neighbor distances, respectively. The results suggest that the viscosity anomaly in liquid KCl strongly correlates with the structural changes. The integration of the viscosity and liquid structure measurements opens a new way for further understanding the dynamics of liquids at high pressures.
(See Kono et al., Phys. Rev. B 87, 024302, 2013)