Analysis of Ar visible spectra in inductively coupled plasma

Spectroscopic measurement has been carried out for identification of chemical species in inductively coupled Ar plasma. In addition, the excitation temperature has been calculated for each condition by the Boltzmann plot, using relative intensities of spectra for neutral Ar. Only ionized Ar+ lines were observed at 133 Pa in the low pressure range, while only neutral Ar lines were observed at 8.0 × 103 Pa in high pressure range. At 667 Pa and 8.0 × 103 Pa in high pressure range, the plasma is reached an almost local thermodynamic equilibrium (LTE) and excitation temperatures for these pressure conditions could be calculated. The results indicated temperatures were about 7800 K and 6400 K, respectively.