Measured Stark widths and shifts of the neutral argon spectral lines in 4s–4p and 4s–4p′ transitions

Abstract

We investigate the Stark widths ( W) and the shift ( d), of the seven neutral argon (Ar I) spectral lines from the 4s–4p and 4s–4p′ transitions. The line shapes are measured in a linear, low-pressure, optically thin pulsed arc discharge at about 16 000 K electron temperature ( T) and about 7.0 × 10 22 m − 3 electron density ( N). The new data separates the electron width ( W e) and ion width W i from the total Stark width ( W t), as well the separation of electron total Stark shift ( d t) on electron ( d e) and ion ( d i) parts. There are no theoretical predictions for these lines. Comparison to theoretical predictions for other lines within the same multiplets finds that the experimental data exhibits stronger influence by the ion contribution to the measured Ar I line shape. We have also deduced the ion broadening parameters which describe the influence of the ion static ( A) and the ion–dynamical ( D and E) effect on the width and the shift of the line shape. Applying the line deconvolution procedure, the basic plasma parameters i.e. electron temperature ( T) and electron density ( N) are recovered. The plasma parameters ( T and N) are measured using independent diagnostics techniques as well. Good agreement is found among two sets of the N and T plasma parameters obtained from deconvolution procedure and independent diagnostics techniques.