The atomic processes in laser-produced tin plasmas for the extreme ultraviolet light sources are investigated. The level population of complex tin ions is calculated using the collisional-radiative (CR) model, and then spectral emissivity and opacity are calculated, taking the spectral structure of unresolved transition array into account. A rule-based method for developing a large-scale CR model is discussed, which enables the simulation of the emission spectrum using a relatively compact model. The effect of configuration interaction on the wavelength of the emission and broadening of the main peak at λ = 13.5 nm by the emission from multiply excited states is discussed.
SASAKI et al. (2026) studied this question.