Emission spectrum and the excitation/ionization of nickel in an argon glow discharge

The excitation of Ni I and Ni II emission spectra in an argon glow discharge was analyzed and compared with that of some other transition elements. Higher Ni I levels are enhanced compared to the trend corresponding to the Boltzmann distribution. Selective excitation of some Ni II levels was observed and attributed to the (Ar+-Ni0) charge transfer reaction. [Display omitted] •Ni I and Ni II emission spectra in argon glow discharge were analyzed.•Ni I experimental Boltzmann plot is presented.•Ni II transition rate diagram is presented.•The Ar+-Ni0 charge transfer reaction populates some Ni II levels.•The results are compared with the excitation of iron.