Mobility and longitudinal diffusion of SF₅⁻and SF₆⁻in SF₆

The drift and longitudinal diffusion of SF 5 - and SF 6 - in SF 6 has been studied with a drift-tube mass spectrometer. Values of the reduced mobility and of the density-normalized longitudinal diffusion coefficient of these ions are reported over the combined E/N range 15-460 Td. The present zero-field reduced mobilities for both ions are in excellent agreement with those of Patterson (1972). To the authors' knowledge, the present data are the first measured with simultaneous mass analysis over the entire E/N range.