The Mobility of Negative Ions in CF3I, CF3I-N2, CF3I-Ar, CF3I-Xe, C2F6, and CHF3, and of Positive Ions in C2F4 and c-C4F8

Using a pulsed Townsend technique, the drift velocity and the mobility of positive ions in C2F4 and C4F8 and those of negative ions in C2F6, CHF3, and CF3I and its mixtures with N-2, Ar, and Xe are reported. The overall range of the density-normalized electric field is 4-600 x 10(-17) V . cm(2). Ion identification is provided by means of previous studies on partial ionization and electron attachment. Thus, it is suggested that the predominant drifting ion in the discharge is C2F4+ for C2F4 and c-C4F8, F- for C2F6 and CHF3, and I- for CF3I. The use of more comprehensive theories of ion motion considering the influence of a permanent dipole moment (CHF3 and CF3I) has provided reasonable agreement between low-field measured and calculated mobilities. The mobility of negative ions in CF3I-N-2, CF3I-Ar, and CF3I-Xe mixtures agrees reasonably well with the predicted values by Blanc's law.