Anomaly in the viscosity of liquid KCl at high pressures

Yoshio Kono, Curtis Kenney-Benson, Changyong Park, Guoyin Shen, Yanbin Wang
2013 Physical Review B  
We measured viscosity of KCl and NaCl liquids up to 7.3 GPa and observed a clear discontinuity in the pressure dependence of viscosity for liquid KCl at around 2 GPa. The viscosity of liquid KCl increased rapidly at 1.5-2.2 GPa, above which it remained virtually constant. Structural data of KCl liquid also showed a pronounced change signified by the ratio r 2 /r 1 , where r 1 and r 2 are the nearest-and the second-neighbor distances, respectively. In contrast, both viscosity and the r 2 /r 1
more » ... and the r 2 /r 1 ratio changed linearly with pressure for liquid NaCl. Our observation suggests that viscosities of KCl and NaCl liquids strongly correlate with the structural changes in terms of the r 2 /r 1 ratio. The viscosity anomaly in liquid KCl is found to be at pressures close to that of the B1-B2 transition in solid KCl. Pressure-induced structural changes and associated physical properties in liquids are among the most fundamental and challenging topics in condensed matter physics. Pressureinduced structural transition has been studied both experimentally and theoretically in several liquids, such as phosphorus [1], nitrogen [2], silicon [3], selenium [4], tellurium [5], and water
doi:10.1103/physrevb.87.024302 fatcat:lakqyvfmrzgibffoxut7tueauy