Positive ion mobilities in helium vapor

Abstract

The zero-field mobilities of positive helium ions in helium vapor have been measured as functions of both pressure and temperature between 2.0 and 5.2\ifmmode^\circ\else\textdegree\fi{}K. These mobilities are much lower than would be predicted from known ion mobilities at 76\ifmmode^\circ\else\textdegree\fi{}K. These data can be explained in terms of kinetic theory with a clusteredion hypothesis.