Excitation of Doubly‐Charged Ion Emission Lines from a Grimm‐Style Glow Discharge Plasma—Comparison Between Yttrium and Zirconium

Abstract

Spectra of yttrium and zirconium emitted from a Grimm‐style glow discharge plasma were investigated to elucidate the excitation mechanism of doubly‐charged ionic lines when using argon–helium mixed gas as well as argon gas alone. The energy sum for exciting doubly‐charged ion species of yttrium is slightly smaller compared to the case of zirconium, which yields an interesting correlation in the excitation energy between their ionic species and excited species of helium or argon. The Y III emission lines which were assigned to the 4p⁶5p–4p⁶5s(4p⁶4d) transitions could be observed in the argon–helium mixed gas plasma, but those were hardly excited with argon gas only. The Zr III emission lines did not appear in the spectra emitted by the argon gas plasma nor by the mixed gas plasma. A possible explanation for these phenomena is that the excitation of these ionic species is caused principally by collisional energy transfer from helium species to the analyte atoms.

Keywords:

• Doubly‐ionized emission lines
• Yttrium
• Zirconium
• Glow discharge plasma
• Argon
• Argon–helium mixed gas
• Excitation and ionization mechanism
• Collision of the second kind

Acknowledgment

This study was in part supported by a grant‐in‐aid from the Ministry of Education of Japan (No. 15560705).