Analysis of unresolved transition arrays in XUV spectral region from highly charged lead ions produced by subnanosecond laser pulse

Abstract Soft x-ray and extreme ultraviolet (XUV) spectra from lead (Pb, Z=82) laser-produced plasmas (LPPs) were measured in the 1.0–7.0 nm wavelength region employing a 150-ps, 1064-nm Nd:YAG laser with focused power densities in the range from 3.1×10 13  W/cm 2 to 1.4×10 14  W/cm 2 . The flexible atomic code (FAC) and the Cowan's suite of atomic structure codes were applied to compute and explain the radiation properties of the lead spectra observed. The most prominent structure in the spectra is a broad double peak, which is produced by Δ n =0, n =4–4 and Δ n =1, n =4–5 transition arrays emitted from highly charged lead ions. The emission characteristics of Δ n =1, n =4–5 transitions were investigated by the use of the unresolved transition arrays (UTAs) model. Numerous new spectral features generated by Δ n =1, n =4–5 transitions in ions from Pb 21+ to Pb 45+ are discerned with the aid of the results from present computations as well as consideration of previous theoretical predictions and experimental data.