Ionic Mobilities in Argon and Helium Liquids

The mobilities of ions and electrons have been measured in liquid argon at 90° K., and in liquid helium from 4.2° to 1.4° K. The electron behavior in liquid argon can be explained in terms of gas kinetic theory, while the positive ion behavior in both liquids cannot. Stokes' law predicts the ionic behavior at the boiling points of the two liquids. Electrons in liquid helium have very small mobilities, approximately one-quarter the value for the positive ions, suggesting a wide departure from the electron behavior in argon. Below 2.19° K. both the electronic and ionic mobilities become temperature and electric field dependent.