Boltzmann statistical consideration on the excitation mechanism of iron atomic lines emitted from glow discharge plasmas

Lei Zhang, Shunsuke Kashiwakura, Kazuaki Wagatsuma

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

A Boltzmann plot for many iron atomic lines having excitation energies of 3.3-6.9 eV was investigated in glow discharge plasmas when argon or neon was employed as the plasma gas. The plot did not show a linear relationship over a wide range of the excitation energy, but showed that the emission lines having higher excitation energies largely deviated from a normal Boltzmann distribution whereas those having low excitation energies (3.3-4.3 eV) well followed it. This result would be derived from an overpopulation among the corresponding energy levels. A probable reason for this is that excitations for the high-lying excited levels would be caused predominantly through a Penning-type collision with the metastable atom of argon or neon, followed by recombination with an electron and then stepwise de-excitations which can populate the excited energy levels just below the ionization limit of iron atom. The non-thermal excitation occurred more actively in the argon plasma rather than the neon plasma, because of a difference in the number density between the argon and the neon metastables. The Boltzmann plots yields important information on the reason why lots of Fe I lines assigned to high-lying excited levels can be emitted from glow discharge plasmas.

Original languageEnglish
Pages (from-to)785-792
Number of pages8
JournalSpectrochimica Acta - Part B Atomic Spectroscopy
Volume66
Issue number11-12
DOIs
Publication statusPublished - 2011 Nov 1

Keywords

  • Boltzmann plot
  • Excitation mechanism
  • Glow discharge optical emission spectrometry
  • Iron
  • Plasma gas

ASJC Scopus subject areas

  • Analytical Chemistry
  • Atomic and Molecular Physics, and Optics
  • Instrumentation
  • Spectroscopy

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