Ground-state configurations and unresolved transition arrays in extreme ultraviolet spectra of lanthanide ions

Abstract

Theoretical ground-state configurations of lanthanide ions calculated with the Cowan suite of codes are presented. Theoretical 4d -4f and 4p -4d spectra of Pd-like to Rb-like lanthanide ions calculated using the FAC relativistic code are also shown. The effects of configuration interaction are investigated and results compare favorably with experiments where, for increasing nuclear charge, strong emission peaks are observed to move towards shorter wavelength. The application of these strong emitters as extreme ultraviolet radiation sources, a topic of emerging interest, is discussed.

Optimizing conversion efficiency and reducing ion energy in a laser-produced Gd plasma

“…With the resolution of many of the problems involved with 13.5 nm tin (Sn) plasma sources [1], much research has already begun to shift towards shorter wavelength source development. Modeling work has proceeded on several high-Z materials [2,3], with gadolinium (Gd) laser produced plasmas (LPPs) becoming the focus of significant effort [4]. The choice of Gd arises from the fact that the same transition array that is responsible for emission at 13.5 nm in Sn plasmas lies in the reflection region of lanthanum boron carbide (La/B 4 C) multilayer mirrors, close to 6.7 nm.…”

Resolution of hyperfine transitions in metastableKr83using electromagnetically induced transparency

“…The values of A and B parameters obtained in this work have been compared with those reported in the previous works. Our EIT based method can be useful in the resolution of spectrally rich transitions in other atoms and molecules also, including the hyperfine transitions in other noble gas atoms [39,40] and weak transitions in heavy atoms [41].…”

Scaling of laser produced plasma UTA emission down to 3 nm for next generation lithography and short wavelength imaging

“…This figure shows the calculated positions of the strongest n = 4-n = 4 transitions for four stages of each element corresponding to Ru-like (red) , Rh-like (blue), Pd-like (green) and Ag-like (black) ions. From this plot it is clear that maximum overlap between emission from different stages occurs in the lanthanides and corresponds from an atomic physics viewpoint to the localization of the 4f wavefunction in the ionic core where its overlap with the 4d changes little with ion stage [26]. For lower Z elements the emission extends over a broader energy range due to differing degrees of 4f localization while the 4p spin orbit splitting causes the emission to diverge to form two emission regions at the higher Z end.…”