Transition rate diagrams and excitation of titanium in a glow discharge in argon and neon

• Published in: Spectrochimica acta. Part B: Atomic spectroscopy 2018-06, Vol.144, p.20-28
• Main Authors: Weiss, Zdeněk, Steers, Edward B.M., Pickering, Juliet C.
• Format: Article
• Language: English
• Subjects: Argon; Argon ions; Charge transfer; Chemicals; Diagrams; Discharge; Emission spectra; Emission spectroscopy; Energy; Excitation; Glow discharge; Glow discharges; Ground state; Ionization; Ions; Neon; Spectra; Spectrum analysis; Titanium; Transition rate diagrams
• ISSN: 0584-8547; 1873-3565
• DOI: 10.1016/j.sab.2018.03.003

Emission spectra of titanium in a Grimm-type glow discharge in argon and neon were studied using the formalism of transition rate diagrams. Ti I spectra in argon and neon discharges are similar, without signs of selective excitation, and populations of Ti I levels exhibit a decreasing trend as function of energy, except for some scatter. A major excitation process of Ti II in argon discharge is charge transfer from argon ions to neutral titanium. In neon discharge, a strong selective excitation was observed of Ti II levels at ≈13.3–13.4 eV relative to the Ti I ground state. It was attributed to charge transfer from doubly charged titanium ions to neutral titanium, while the Ti++ ions are produced by charge transfer and ionization of neutral titanium by neon ions. Cascade excitation is important for Ti II levels up to an energy of ≈13 eV relative to the Ti I ground state, both in argon and neon discharges. [Display omitted] •Ti I and Ti II transition rate diagrams in Ar and Ne glow discharges are presented.•Ti I spectra in Ar and Ne discharges are similar, without selective excitation.•Excitation of Ti II in Ar discharge is dominated by charge transfer from Ar+ to Ti0.•In Ne discharge, Ti II excitation involves charge transfer from Ti++ ions to Ti0.•In Ne discharge, Ti++ ions are created by Ne+ − Ti0 charge transfer and ionization.