Surface-Induced Transitions in Highly Excited Noble-Gas Ions and Quasimetastable Peaks in the Mass Spectra of the Noble Gases

The appearance of some quasimetastable peaks in the mass spectra of the noble gases is shown to be due to a surface‐induced transition of the type: $${\mathrm{X}}^{\mathrm{(q)+*}}\to {\displaystyle {lim}^S}{\mathrm{X}}^{\text{(q+1)+}}{\mathrm{+e}}^{-}$$ in which X is any of the noble gases and S represents a metal surface. In argon, peaks arising from this type of transition at the ion‐source first slit, focus slit, and last slit, respectively, have been observed and characterized as to (1) their behavior with the voltage effective at each respective slit, (2) their kinetic energy as measured by the metastable‐ion‐suppressor cutoff behavior, and (3) their appearance potential. These peaks are postulated to arise from ions in Rydberg levels of high principal quantum number at an excitation level near the next higher ionization potential. Possible mechanisms for the transition are discussed.