Isotope effects on vibrational transition probabilities. III. Lonization of isotopic H₂, N₂, O₂, NO, CO, and HC1 molecules

Franck-Condon factors are given for the normal and stable isotope-labeled molecules for transitions to spectroscopically known ionic states. Appreciable isotope effects on Franck-Condon factors are found in several transitions, and are related both to the differences in internuclear separation associated with different levels and to differences in reduced masses. Isotopic substitution by a heavier element results in a shift in the transition probability towards higher vibrational levels. Therefore an inversion in the ratio of ionization efficiencies of light and heavy molecules is predicted.