Isotope Effect on Charge Transfer Cross Sections of Slow ⁷Li⁺ Ions in Collisions with H₂, HD, and D₂ Molecules

Abstract

Charge transfer cross sections of ⁷Li⁺ ions in collisions with H₂, HD, and D₂ molecules have been measured in the energy range from 1.4 to 4.0 keV using the growth rate method. Significant differences in the charge transfer cross sections between collisions of ⁷Li⁺ ions with H₂ and HD, and with H₂ and D₂ molecules, the socalled target isotope effect, are observed at collision energies from 1.4 to 2.4 keV. The observed charge transfer cross section ratios of σ (HD)/σ (H₂) and σ (D₂)/σ (H₂) are found to be approximately 0.7 at 1.4 keV. They are gradually increasing, and finally approaching unity at energies above 2.4 keV.