Anomalous loss of ionization in argon-hydrogen plasma studied by fast flow glow discharge mass spectrometry

Journal Article · Sun Jun 01 04:00:00 EDT 1997 · Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics

DOI:https://doi.org/10.1103/PhysRevE.55.7462· OSTI ID:548816

Mason, R S; Miller, P D; Mortimer, I P ^[1]

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1. Department of Chemistry, University of Wales Swansea, Singleton Park, Swansea SA28PP (United Kingdom)

Changes in ion abundance from the plasma of an abnormal dc glow discharge, using a copper cathode, have been studied as a function of (a) gas residence time in the discharge and (b) the amount of H{sub 2} added to the positive column, without disturbing the discharge. The Ar+H{sub 2} spectra show a severe, but selective, quenching of the ionization. All major ions are quenched except for Cu{sup +}, which increases in abundance. It is shown that this cannot be explained by either ion-molecule reactions or the fast recombination suggested previously [R. F. G. Meulenbroeks {ital et al.}, Phys. Rev. E {bold 49}, 4397 (1994)] for such mixtures. The kinetic behavior is consistent with the heavy involvement of stepwise ionization processes in which high excited metastable states of neutral Ar are precursors for most ions observed in the spectrum. It is proposed that these states are rapidly quenched by H{sub 2} down to the Ar(4s) levels, preventing ionization of most species in the discharge, but significantly boosting the Penning ionization of Cu atoms sputtered from the cathode. {copyright} {ital 1997} {ital The American Physical Society}

• OSTI ID: 548816
• Journal Information: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics, Journal Name: Physical Review. E, Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics Journal Issue: 6 Vol. 55; ISSN 1063-651X; ISSN PLEEE8
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ARGON
CATHODES
CHARGE STATES
COPPER
EXCITED STATES
GLOW DISCHARGES
HYDROGEN
ION-MOLECULE COLLISIONS
IONIZATION
PLASMA