Isotope Effects on Vibrational Transition Probabilities. III. Ionization of Isotopic H2, N2, O2, NO, CO, and HCl Molecules

Abstract

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.