Experimental ion contribution to the Stark broadening of neutral-nitrogen spectral lines in the vacuum uv

The ion contribution to the Stark broadening, as described by a suitably defined asymmetry function AL, was investigated from the asymmetry behavior of the vacuum-uv spectral lines of N I at 119.955 nm (⁴P→⁴S⁰), 141.194 nm (²D→²P⁰), 149.467 nm (²P→²D⁰), and 174.273 nm (²P→²P⁰). The line radiation, which was emitted under controlled optical depths, was generated in a dense equilibrium plasma (wall-stabilized arc; electron number density 4.0×10²² m^-3≤nₑ≤3.7×10²³ m^-3; temperature 11000≤T≤15000 K). Deviations between experimental asymmetry functions of this study and those calculated from recently published data by Griem, have been found for the wings of N I 119.955 nm (normalized wavelength distance from the line center ΔλΔλ1/2≥1; ALGriem-ALᵗʰⁱˢˢᵗᵘᵈʸ≤0.1). For N I 141.194, N I 149.467, and N I 174.273 nm, the asymmetry functions based on line profiles calculated by Griem are in agreement with the asymmetry functions of this study within the given uncertainties. In addition, Stark-width and Stark-shift parameters were experimentally determined for the N I spectrum between 118 and 180 nm. The Stark-width parameters calculated by Griem and by Wilson and Nicolet agreed with the data of this study within ±{} 20%. Only for N I 131.054 and N I 132.663 nm did the Stark-width parameters calculated by Wilson and Nicolet deviate from the corresponding values of this study by approximately + 31%. The calculated Stark-shift parameters of Wilson and Nicolet, however, were considerably higher than the corresponding data of this study (maximum deviation + 78%), whereas the Stark-shift parameters calculated by Griem showed smaller deviations from the data of this study (maximum deviation + 49%).