Mobilities of singly and doubly charged rare-gas ions in helium and in neon

Mobilities of singly and doubly charged ions of neon, argon, krypton, and xenon in helium and of xenon in neon have been determined in a drift-tube mass-spectrometer apparatus at temperatures near 300 K and for $10\le \frac{E}{N}\le 100$ Td. The zero-field reduced mobility of a given doubly charged ion is found to be either equal to or slightly smaller than that of its singly charged counterpart. However, the dependences of the mobilities on $\frac{E}{N}$ are found to be strikingly different for the two cases. No difference in mobility is observed between doubly charged ions in the low-lying, metastable states and in their ground state, in contrast to the case of the ions drifting in their parent gases.