Partial Grotrian diagram (from left to right: singlet, triplet, and quintet electron systems) of our Tc vi model ion. Horizontal bars indicate 555 atomic levels, lines represent radiative transitions (thin, gray: 549 lines with log gf ≥ 0.1; thin, black: 64 lines with log gf ≥ 1.0; thick, red: 52 lines in the 1150 Å ≤ λ ≤ 1780 Å interval with log gf ≥ 0.1). The ten lines with the largest gf values (0.46 ≤ log gf ≤ 1.08, the two strongest are Tc viλλ 1189.28,1269.116 Å), and Tc viλ 1473.702 Å are labeled with their wavelengths.