On the similarity between the energy characteristics of strontium and europium

Resumo

The spectra of Eu, Sr, Eu⁺, and Sr⁺ are used as examples to demonstrate the similarity between the energy characteristics of these elements. It is shown that europium is identical to strontium in the strong and inhomogeneous magnetic field whose source in lanthanides is their empty and compact 4f^{n < 14} core. It is concluded that when it is missing from europium, the latter becomes identical to strontium with no magnetic fields.