4d excitation spectra of highly charged Pr ions in laser-produced plasmas

Spectra of laser-produced praseodymium (Pr) plasmas have been acquired for the 7.5–14.5 nm wavelength range using spatio-temporally resolved emission spectroscopy. The characteristic features of experimental spectra are dominated by an intense narrow band and a broad quasi-continuous band. These derive from 4d-4f transitions of Pr3+ up to Pr7+ ions, according to Hartree-Fock calculations that evaluated configuration interaction effects. Plasma parameters have been estimated by comparing experimental and simulated spectra, based on the assumption of a normalized Boltzmann distribution among excited states and a steady-state collisional-radiative model. The results provide further understanding of radiation properties of highly charged ions of middle- and high-Z elements.