EUV spectra of europium—Chasing for spectral lines of P‐ to Ar‐like ions

Abstract

The understanding of atomic structure implies a combination of accurate measurements and a reliable theoretical framework. Atomic structure computations are employed to bridge the many gaps in the experimental data, but their results need to be tested by measurements. We have selected extreme ultraviolet (EUV) spectra of europium (Eu, Z=63) for such tests. We study the emission spectra of Eu ions produced and excited in an electron beam ion trap by observation with highly resolving spectrographs. General purpose atomic structure computations help us at disentangling the spectra and identifying the emission of specific charge state ions. At the same time the wavelength data provide a tool to judge the quality of the computations. The present study concentrates on ions of the charge states q = 45+ to q = 49+, or P-to Ar-like ions of Eu.

Measurements of L‐shell X‐ray emission lines of neonlike europium on an electron beam ion trap

“…Injection of europium into the ion trap was achieved by the evaporation of europium atoms from a heated sample, as described by Magee et al [24]. This method has been employed successfully already for several spectroscopic measurements of europium [25][26][27].…”