Mobility of Electrons in Dielectric Liquids

The drift mobilities of electrons in eight saturated hydrocarbons and in tetramethylsilane were determined from the rise time in the conductivity found with a fast-response circuit when a parallel-plate cell was subjected to a pulse of 2-MeV x rays. Careful purification was required to avoid capture of the electrons by impurity centers. The measured mobilities ranged from 0.09 cm2 V−1·sec−1 in n-hexane to 90 in tetramethylsilane. Drift velocities were linear with the applied field up to velocities above 106 cm/sec. Temperature coefficients of the mobility were found to be positive in n-hexane and neohexane. Speculations are offered about the nature of the processes which determine the mobilities.