Experimental determination of the Stark widths of Pb I spectral lines in a laser-induced plasma

Abstract

Stark widths of 34 spectral lines of Pb I have been measured in a Laser-Induced-Plasma (LIP). The optical emission spectroscopy from a LIP generated by a 10640 Å radiation, with an irradiance of 1.4 × 10¹⁰ W cmˉ² on a Sn–Pb target in an atmosphere of argon was analyzed between 1900 and 7000 Å. The Local Thermodynamic Equilibrium (LTE) conditions and plasma homogeneity have been checked. The 34 spectral lines measured in this paper correspond to the transitions n(n=7,8)s→6p², n(n=6,7)d→6p². The population levels distribution and the corresponding temperatures were obtained using Boltzmann plots. The plasma electron densities were determined using well-known Stark broadening parameters of spectral lines. Special attention was dedicated to the possible self-absorption of the different transitions. Stark broadening parameters of the spectral lines were measured at 2.5 µs after each laser light pulse, where the electron temperature was close to 11200 K and the electron density to 10¹⁶ cmˉ³. The experimental results obtained have been compared with the experimental values given by other authors.