Feasibility of Using Boltzmann Plots to Evaluate the Stark Broadening Parameters of Cu(I) Lines

Appl Spectrosc. 2021 Oct;75(10):1288-1295. doi: 10.1177/00037028211013371. Epub 2021 May 26.

Abstract

A linear Boltzmann plot was constructed using Cu(I) lines of well-known atomic parameters. Aligning other spectral lines to the plot was adopted as a viable way to estimate the most probable values of Stark broadening parameters of Cu(I) lines at 330.79, 359.91, and 360.2 nm. Plasma was generated by focusing neodymium-doped yttrium aluminum garnet (Nd:YAG) laser radiation at wavelength 532 nm on a pure copper target in open air. Plasma emission was recorded at delay times of 3, 4, 5, 7, and 10 μs. The in situ optically thin Hα line was used to determine the plasma reference electron density over the entire experiment. Following this method, the missing values of the Stark broadening parameters of the three Cu(I) lines turn out to be about 0.15 ± 0.05 Å (for 330.79 nm transition) and 0.17 ± 0.05 Å (for 359.91 360.20 nm transition) at reference electron density of (1 ± 0.09) × 1017 cm-3 and temperature of 10 800 ± 630 K. The apparent variation in plasma parameters at different delay times was found to scale with electron density and temperature as ne.Te0.166.

Keywords: Boltzmann plot method; Cu(I) spectral lines; LIBS; Laser-induced breakdown spectroscopy; Stark broadening coefficient; transition probability.