Theoretical calculation of the energy spectrum and oscillator strengths of Tc II

Radiative decay of the 4d5(6S)5p z5,7Po states in Tc II: comparison along the homologous and isoelectronic sequences. Application to astrophysics

“…While some recent works have provided a number of results in neutral technetium (Palmeri & Wyart 1999;O'Malley & Beck 2003;Palmeri et al 2005a), no similar attempts exist for singly ionized technetium. To our knowledge, the only transition probabilities available in Tc II are due to Bakhtiyarov (1988). These results however were obtained through single-configuration calculations and the length-form data differed substantially (up to 40 per cent) from the velocity-form results.…”

“…It is generally believed that these technetiumpoor stars are resulting from a totally different evolutionary scheme: the accretion long ago of s-process-rich matter from a companion, in a binary system, explains their chemical peculiarities and the absence of Tc (see e.g. Smith & Lambert 1987, 1988Jorissen & Mayor 1988, 1992Brown et al 1990;Johnson, Ake & Ameen 1993;Jorissen et al 1993).…”

About possible explanations to the lines of radioactive elements in the spectrum of Przybylski's star

“…We used the list of oscillator strengths of lines of the first and second spectra of Tc published in [3,1,15] and other papers. Kurucz partition functions and ionization potentials were used.…”