Kinetics of highly vibrationally excited O<SUB>2</SUB> (X) molecules in inductively-coupled oxygen plasmas - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Plasma Sources Science and Technology Année : 2018

Kinetics of highly vibrationally excited O2 (X) molecules in inductively-coupled oxygen plasmas

Adriana Annusova
  • Fonction : Auteur
Jean-Paul Booth
Nishant Sirse
  • Fonction : Auteur
Mrio Lino Da Silva
  • Fonction : Auteur
B. Lopez
  • Fonction : Auteur
V. Guerra
  • Fonction : Auteur

Résumé

The high degree of vibrational excitation of O 2 ground state molecules recently observed in inductively coupled plasma discharges is investigated experimentally in more detail and interpreted using a detailed self-consistent 0D global kinetic model for oxygen plasmas. Additional experimental results are presented and used to validate the model. The vibrational kinetics considers vibrational levels up to v = 41 and accounts for electron impact excitation and de-excitation (e-V), vibration-to-translation relaxation (V-T) in collisions with O 2 molecules and O atoms, vibration-to-vibration energy exchanges (V-V), excitation of electronically excited states, dissociative electron attachment, and electron impact dissociation. Measurements were performed at pressures of 10?80 mTorr (1.33 and 10.67 Pa) and radio frequency (13.56 MHz) powers up to 500 W. The simulation results are compared with the absolute densities in each O 2 vibrational level obtained by high sensitivity absorption spectroscopy measurements of the Schumann?Runge bands for O 2 ( X , v  = 4?18), O( 3 P ) atom density measurements by two-photon absorption laser induced fluorescence (TALIF) calibrated against Xe, and laser photodetachment measurements of the O ? negative ions. The highly excited O 2 ( X , v ) distribution exhibits a shape similar to a Treanor-Gordiets distribution, but its origin lies in electron impact e-V collisions and not in V-V up-pumping, in contrast to what happens in all other molecular gases known to date. The relaxation of vibrational quanta is mainly due to V-T energy-transfer collisions with O atoms and to electron impact dissociation of vibrationally excited molecules, e O 2 ( X , v )?O( 3 P) O( 3 P).
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Dates et versions

hal-01895558 , version 1 (15-10-2018)

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Adriana Annusova, Daniil Marinov, Jean-Paul Booth, Nishant Sirse, Mrio Lino Da Silva, et al.. Kinetics of highly vibrationally excited O2 (X) molecules in inductively-coupled oxygen plasmas. Plasma Sources Science and Technology, 2018, 27 (4), pp.045006. ⟨10.1088/1361-6595/aab47d⟩. ⟨hal-01895558⟩
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