Negative ion formation by Rydberg electron transfer: Isotope-dependent rate constants

摘要

The formation of negative ions during collisions of rubidium atoms in selected ns and nd Rydberg states with carbon disulfide molecules has been studied for a range of effective principal quantum numbers (10 (le) n* (le) 25). For a narrow range of n* near n* = 17, rate constants for CS(sub 2)(sup (minus)) formation are found to depend upon the isotopic composition of the molecule, producing a negative ion isotope ratio (mass 78 to mass 76, amu) up to 10.5 times larger than the natural abundance ratio of CS(sub 2) isotopes in the reagent. The isotope ratio is found to depend strongly upon the initial quantum state of the Rydberg atom and perhaps upon the collision energy and CS(sub 2) temperature. 32 refs., 5 figs., 1 tab.