Mobilities of doubly charged rare-gas ions in their parent gases

The mobilities of the doubly charged rare-gas ions ${\mathrm{He}}^{2+}$, ${\mathrm{Ne}}^{2+}$, ${\mathrm{Ar}}^{2+}$, ${\mathrm{Kr}}^{2+}$, and ${\mathrm{Xe}}^{2+}$ in their parent gases have been determined in a drift-tube mass-spectrometer apparatus. The finding of more than one mobility for each of the doubly charged ions (with the exception of ${\mathrm{He}}^{2+}$) is attributed to the presence of the ${}_{}{}^3{}_{}{}^{}P$, ${}_{}{}^1{}_{}{}^{}D$, and ${}_{}{}^1{}_{}{}^{}S$ long-lived, lowest-energy states of these ions. At 300 K the reduced mobilities (in units of ${\mathrm{cm}}^2$/V sec) extrapolated to zero field have the values ${\mu }_0\left({\mathrm{He}}^{2+} \mathrm{in}\mathrm{He}\right)=18.3\mathrm{}$; ${\mu }_0\left({\mathrm{Ne}}^{2+} \mathrm{in}\mathrm{Ne}\right)=6.5\left({}_{}{}^1{}_{}{}^{}D\right), 7.0\left({}_{}{}^3{}_{}{}^{}P\right), 8.5\left({}_{}{}^1{}_{}{}^{}S\right)$; ${\mu }_0\left({\mathrm{Ar}}^{2+} \mathrm{in}\mathrm{Ar}\right)=2.7\left({}_{}{}^3{}_{}{}^{}P\right), \sim 2.2\left({}_{}{}^1{}_{}{}^{}D\right)$; ${\mu }_0\left({\mathrm{Kr}}^{2+} \mathrm{in}\mathrm{Kr}\right)=1.11\mathrm{} \mathrm{and} 1.28$; ${\mu }_0\left({\mathrm{Xe}}^{2+} \mathrm{in}\mathrm{Xe}\right)=0.65\mathrm{} \mathrm{and} 0.75$. The measured values are accurate to ±3%.