Ionization of Inert Gases by Positive Alkali Ions

Abstract

The ionization potentials of the noble gases under impact of various positive alkali ions have been determined in a new and independent manner which employs the neutralization of an electron space-charge by the newly formed positive ions to show the ionization. The method is extremely sensitive to the positive ions but is not affected by the secondary electrons which are liberated from the walls. The potentials found are different for each combination of gas and alkali ion and range in value from 5 to 20 times the electron ionization potentials. They are lower, by amounts running as high as 45 volts in some cases, than those found by Beeck and Mouzon. No ionization was observed by ${\mathrm{Li}}^{+}$ ions, none by ${\mathrm{Na}}^{+}$ ions except in Ne gas, or in Ne gas by any ions but ${\mathrm{Na}}^{+}$. When the actual energies available for ionization, after conservation of energy and momentum have been taken into account, are calculated, the results are strikingly self-consistent, whereas the unreduced results are not at all so. Certain results published by Beeck and Mouzon, but which could not be checked by the author, fail to show this self-consistency.