Boltzmann plot constructed with 44 Cu II lines recorded 120 ns after the laser pulse and at a distance of 2 mm from the copper surface
Figure 4. Boltzmann plot constructed with 44 Cu II lines recorded 120 ns after the laser pulse and at a distance of 2 mm from the copper surface. The symbols \Box, and ▵ represent transition probabilities (A) taken from [1, 16] and , respectively. The line intensities (I) were obtained as values proportional to the area under the line profile fitted to the Voigt function. Wavelengths (λ), statistical weights (g) and upper energy levels (Eu) were taken from the same references.
In this work we present the Stark widths (W) of 22 neutral (Cu I) and 100 singly ionized (Cu II) copper spectral lines that have been measured at 18 400 K and 19 300 K electron temperatures and 6.3 × 10 22 m−3 and 2.1 × 10 23 m−3 electron densities, respectively. The experiment is conducted in the laser-induced plasma—the Nd:YAG laser, operating at 532 nm, was used to produce plasma from the copper sample in the residual air atmosphere at a pressure of 8 Pa. The electron temperature and density were estimated by the Boltzmann-plot method and from the Saha equation. The investigated Cu I lines belong to the 4s–4p', 4s 2–4p'' and 4p'–4d' transitions while Cu II spectral lines belong to the 4s–4p, 4p–5s, 4p–4d, 4p–4s 2, 4d–4f and 4d–v transitions. Comparison with existing experimental data was possible only in the case of 17 Cu II lines due to a lack of experimental and theoretical values. The rest of the data, Stark widths of 22 Cu I and 83 Cu II lines are published for the first time.