ИСТИНА

Study of plasma emission plays an important role in analytical chemistry, interpretation of meteors’ spectra and astrophysics. The line profile can be disturbed due to Stark effect, and, therefore, Stark broadening parameters are essential for plasma diagnostics or spectra modeling and lack of them results in errors of element abundances calculation. Oxygen and nitrogen are present in laboratory and astrophysical plasmas, and their lines can be used for plasma diagnostics or for study of star-formation processes. Laser-induced plasma provides important advantages for determination of Stark parameters (possibility to choose any target, absence of electrode material and relatively high electron density at low temperature), making it preferable for the parameters determination at the temperature of 5000-30000 K. This range is important for the correct interpretation of meteor spectra due to closeness to temperature of their ablation[1]. By virtue of the foregoing, we focused on determination of Stark shifts and widths of a number of singly ionized oxygen and nitrogen lines in air laser plasma. Methods. For plasma diagnostics and Stark parameters measurements we suggested a novel approach to evaluate the “quality” of a line by thermodynamic spectra modeling (homogeneous LTE plasma, line broadening mechanisms and self-absorption). We used the synthetic spectrum approximated the experimental data to exclude the self-absorbed lines and the lines disturbed by interfering ones (intensity of interferences > 5%). Results and conclusions. The selected nitrogen lines with well-known parameters were used for temperature and electron number density calculation. The impact of other broadening mechanisms is at least 50 times smaller than Stark broadening under our conditions. We measured both Stark shifts and widths for 10 oxygen and nitrogen ionic lines (8 ones have not been previously calculated or measured and the rest values are in a good agreement[2] with previous experimental and theoretical data). Finally, we can conclude that laser plasma is perfect for determination of Stark parameters of atmospheric gases. Supported by RSF (grant 18-13-00269). 1. J. Borovicka, H. Betlem. Planet. Space Sci. 45 (1997) 563-575. 2. N. Konjevic, A. Lesage, J.R. Fuhr, W.L. Wiese. J. Phys. Chem. Data. 31 (2002) 819-927.