Ionization Energy Difference between Isotopes and its Effect on Isotope Abundance Measurement by Surface Ionization Method

Abstract

In mass spectrometric measurement of isotope abundance, it has been assumed that ionization energy is same for isotopes. In this paper the finite nucleus mass effect and finite nucleus volume effect ionization energy are considered. Theoretical calculation and spectroscopic data show that the ionization energy difference between⁷ Li and⁶ Li is 1?10^-4 eV, and only for Li the isotope effect by ionization energy difference can amount to the same order of magnitude as those mass descriminations evaporation of the sample from the filament, by ion optics in the ion source chamber and so on.