Neutral lithium spectral line 460.28 nm with forbidden component for low temperature plasma diagnostics of laser-induced plasma

•Stark broadening parameters of Li I 460.28 nm line with forbidden component•Computer simulation method for overall line profile calculation•Experimental study of Li I line shapes in laser induced plasma.•Comparison of line profile parameters with other experimental and theoretical results•Simple expressions for plasma diagnostics using Li I 460.28 nm line parameters

We present the results of theoretical and experimental line shape study of the Li I 460.28 nm line with a forbidden component in a low temperature laser-induced plasma. For this purpose a computer simulation method is used to calculate the overall line profile in the electron number density range of (0.5–11.0) × 1016 cm- 3 and the electron temperature 5800 K. The same computer simulation method is used to evaluate asymmetric profiles of the isolated Li I 497.17 nm line in the same electron density range and for several electron temperatures between 3500 K and 10 300 K. The results for the Li I isolated line are used together with two other theoretical calculations for independent electron density measurements in laser induced plasma. The electron temperatures in the range of 4000–7000 K were determined from relative Li I line intensities using Boltzmann plot technique. The comparison between calculated profiles and experimental data for the Li I 460.28 nm line with a forbidden component indicates that theoretical results can be used for electron density diagnostics in the aforementioned density range with an accuracy of ± 10–15%. To facilitate the application of theoretical line profiles simple expressions are supplied.