# Laser-Induced Breakdown Spectroscopy for Determination of Spectral Fundamental Parameters
## 5 Experimental Determination of Spectral Parameters by LIBS
### Determination of Stark Broadening Coefficients

Table 1: Applications of LIBS for determining the Stark broadening coefficients of atomic lines. In 1999, [PERSON] and [PERSON] [64] determined the Stark broadening coefficients of 24 Sn II lines and three Sn I lines, in Ar atmosphere. The authors calculated the effect of self-absorption to be below 1%. [PERSON] et al. [65] in 2004 determined the Stark broadening coefficients of 12 Ar I lines, working in low-pressure conditions to avoid self-absorption of the radiation. They used the Ar I line at 703.025 nm as a reference line for the determination of the electron number density. The next year, [PERSON] and [PERSON] [66] calculated the Stark broadening coefficients of 26 lines of singly ionized gold. The measurements were done in Ar atmosphere, and the distribution of the emitters was checked using Abel inversion. The authors evaluated the effects of self-absorption and determined that it affected their calculation for less than 3%. [PERSON] et al. [67] in 2006 studied on iron-nickel alloys the main experimental conditions that must be fulfilled by a LIBS plasma to determine the Stark broadening parameters. The authors found that the plasma inhomogeneity affects the Stark broadening determination with an error below 7%. The Stark broadening of the Fe I line at 381.58 nm was measured using the non-self-absorbed Fe I line at 538.34 nm as a reference for the determination of the electron number density. The effect of self-absorption for a sample with an iron concentration of 2%, was found to be negligible. In the same year, [PERSON] and [PERSON] [68] measured the Stark widths of 31 lines of Pb II. The LIBS experiments were performed on several lead targets, in vacuum and in argon atmosphere. Under 6 Torr of argon atmosphere, and at a delay of 2.5 us after the laser, all the studied Pb II lines did not show self-absorption effects, except for the 220.3 nm line (this line was investigated separately by the same authors in 2019 [91]). After that (in 2007), using the same experimental setup [PERSON] and [PERSON] [69] calculated the Stark widths of ten doubly ionized lead spectral lines (Pb III). Experimental Stark broadenings of 5 Mn I and 9 Mn II lines were determined by [PERSON] et al. in 2007 [70]. Single and double-pulse LIBS configurations were used on a series of Fe-Mn alloy samples with Mn concentration ranging from 6% to 30%. The authors estimated the effect of self-absorption to be lower than 3%. In 2008, [PERSON] et al. [71] determined the Stark widths of 17 Ni II lines. The measurements were done on binary Al-Ni alloy samples with low content of Ni (5% and 2%), in Ar atmosphere. For the most intense lines, the self-absorption factor calculations gave values lower than 2.5%; consequently, the plasma was considered optically thin. In the same year, [PERSON] and [PERSON] [72] studied a Cd-Zn alloy with a Zn content under 10%. The authors calculated the Stark widths of 6 lines of Zn II. To determine the SA effects, the authors found that there was no dependence of the branching ratios on concentration within the range of 5% to 1% of zinc in the sample. \begin{table}
\begin{tabular}{c c c c c} \hline
**Year** & **Authors** & **Ref.** & **Lines** & **Notes** \\ \hline
2019 & [PERSON]. [PERSON] & [90] & 2 Pb IV lines & Calculation of \(k(\lambda_{0})l\) \\ \hline
2019 & [PERSON]. [PERSON] & [91] & 2 Pb II lines & Calculation of \(k(\lambda_{0})l\) \\ \hline
2019 & [PERSON] et al. & [92] & 18 Mo I and 18 Mo II lines & Duplicating mirror technique \\ \hline
2019 & [PERSON] et al. & [93] & 41 Mn II lines widths and 30 Mn II lines shifts & Fused glass samples with varying Mn concentrations \\ \hline
2020 & [PERSON] et al. & [94] & 5 Al II and 8 Al III lines. He I 388.86 nm line width and shift. & Duplicating mirror technique \\ \hline
2020 & [PERSON] et al. & [61] & 4 Ta I and 19 Ta II lines & TIECS method \\ \hline \end{tabular}
\end{table} 
Table 1: Cont. [PERSON] measured by LIBS the Stark widths of 34 spectral lines of Pb I in 2008 [73] and 25 emission lines of Pb III in 2011 [74].