Analysis of the spectrum of the (5d$^6$+5d$^5$6s)−(5d$^5$6p+5d$^4$6s6p) transitions of two times ionized osmium (Os III)

International audienceThe spectrum of osmium was observed in the (225–2100) Å wavelength region. The (5d 6 + 5d 5 6s) − (5d 5 6p + 5d 4 6s6p) transition array of two times ionized osmium, Os III, has been investigated and 1039 spectral lines have been classified in the region. The analysis has led to the determination of the 5d 6 , 5d 5 6s, 5d 5 6p and 5d 4 6s6p configurations. Fifty-eight levels of the 5d 6 and 5d 5 6s configurations in the even system and 142 levels of the 5d 5 6p and 5d 4 6s6p configurations in the odd system have been established. The orthogonal operators technique was used to calculate the level structure and transition probabilities. The energy parameters have been determined by the least squares fit to the observed levels. Calculated transition probability and energy values, as well as LS -compositions obtained from the fitted parameters are presented