Verification of the Existence of Recently Published New Energy Levels of Atomic Holmium
Doğukan Bingöl, Gönül Başar, Günay Başar, İpek Kanat Öztürk, Feyza Güzelçimen, Seda Kın Barka, Sophie KrögerThe objective of this work was to review five energy levels of atomic Holmium that are reported in the literature, for which are indicated that further verification is required. All theoretically possible transitions to these 5 levels were investigated experimentally in the wavelength region of a TiSa laser from 693 nm to 765 nm using laser-induced fluorescence spectroscopy and a hollow cathode discharge lamp. In case a laser-induced fluorescence was detected, the hyperfine structure of the measured lines was fitted and used as fingerprint in the confirmation of the levels under investigation. A total of 20 lines were investigated with laser spectroscopy, but only 2 among those lines were suitable for the intended verification. Therefore, selected lines from a previously measured Fourier Transform (FT) spectra were analysed, additionally. The experimental hyperfine structures were compared with the simulated ones. 9 of the 25 examined FT lines confirm the existence of the levels under investigation. Further 3 FT lines were strongly disturbed by neighbouring overlapped lines. Despite the number of lines, only 2 of 5 levels could be confirmed with high certainty. For the other 3 levels, the lines seen in the FT spectrum were either weak or unresolved, so that confirmation was not possible with a high degree of certainty.
