ELECTRON-MOBILITY IN HIGH-PURITY LIQUID CH4

We have measured the electron mobility in high purity liquid methane as a function of the temperature in the range 92 less-than-or-equal-to T less-than-or-equal-to 122 K, using a pulsed photoemission technique. We have found a mobility 30 to 50% larger than most of the literature data. This discrepancy can be ascribed to the better gas purification method and to the measuring technique as well. Moreover, the mobility data agree fairly well with the Basak and Cohen theory assuming an electron effective mass m* smaller than the electron mass.