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Fast H in hydrogen mixed gas microwave plasmas when an atomic hydrogen supporting surface was present

International Journal of Hydrogen Energy
Publication Date
DOI: 10.1016/j.ijhydene.2009.12.148
  • Hydrogen Mixed Gas Microwave Plasmas
  • Catalysis
  • Fast Hydrogen
  • Balmer Line Broadening
  • Hydrogen Dissociator
  • Chemistry


Abstract Atomic hydrogen is heated to temperatures of up to two orders of magnitude greater than the electron temperature or the temperature of any other species in certain hydrogen mixed gas RF or glow discharge plasmas. A crucial test of energetic hydrogen chemistry regarding a resonant energy transfer or rt-mechanism (RTM) versus field acceleration models (FAM) as the basis of this selective isotropic heating of a population of extraordinarily high-kinetic-energy hydrogen atoms is the observation of fast H in microwave cells proven to lack a high field as shown by the complete absence of fast H (∼0.08 eV) by Jovicevic et al. [S. Jovicevic, N. Sakan, M. Ivkovic, N. Konjevic, J. Appl. Phys. 105, 013306-1 (2009)]. The RTM predicts an enhancement in the production of fast H with the presence of a surface to support a high concentration of hydrogen atoms in order to initiate the energetic hot H source reaction that then propagates isotropically throughout the plasma. In contrast to the prior results, extraordinarily fast H of greater than 4 eV (50 times that observed and deemed possible in the Evenson microwave cell by FAM advocate Jovicevic et al.) and 50% fractional population was observed as predicted for RTM using the catalytic reaction systems of He/H 2, Ar/H 2, pure H 2, and water vapor microwave plasmas when an electrically insulating, but atomic hydrogen supporting material was placed in the plasma region. Increasing concentrations of Xe in the non-catalytic Xe/H 2 system results in a significant decrease in the energy and population of fast excited-state H atoms.

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