Isotope mixing in plasmas of H_2 and D_2 by ion processes and wall reactions

摘要

In order to investigate hydrogen and deuterium isotopic mixing among atoms and ions under controlled conditions, low pressure H_2/D_2 plasmas generated in hollow cathode discharges have been systematically studied. Quadrupole mass spectrometry of neutrals and ions (with energy resolution) and Langmuir probes have been used as diagnostic techniques. The pressures analyzed have been low enough to neglect three body reactions in the gas phase, which enhances the effect of recombination of neutral atoms in the surfaces; but high enough to allow two-body homogeneous reactions between ions and neutrals to become relevant. Both kinds of processes are found to give rise to rich and complex neutral and ion chemistry.