The emission spectrum of doubly ionized holmium was photographed and measured over the region 1900 Å–11 000 Å. A partial analysis of this spectrum was undertaken which resulted in the determination of 42 energy levels of the 4f11, 4f105d, 4f106s, and 4f106p configurations.
No takes yet. Share an insight, caveat, or question.
James Hugh McElaney (1967) studied this question.