Radiative recombination as a transient spectroscopic fingerprint for sample oxidation using laser-induced XUV spectroscopy (LIXS)

The deconvolution of Laser-Induced XUV Spectroscopy (LIXS) recombination signals for d-block transition and heavy metals, in hot and dense plasmas, was studied. Using a self-developed XUV spectrograph, ion stages of nickel (Ni) and gold (Au) under varying electron densities and plasma temperatures were investigated. The results revealed stabilization of specific ion species, with Ni favoring Ne-like configurations and Au exhibiting complex d-f orbital interactions. Supported by non-local thermodynamic equilibrium (NLTE) simulations, this study provides insights into plasma ionization dynamics and the robustness of closed-shell configurations as oxidation state proxies, enhancing LIXS applications in material analysis.