Partial Grotrian diagram (from left to right: doublet, quartet, and sextet electron systems) of our Tc v model ion. Horizontal bars indicate 1932 atomic levels, lines represent radiative transitions (thin, gray: 2117 lines with log gf ≥ 0.1; thin, black: 220 lines with log gf ≥ 1.0; thick, red: 45 lines in the 1150 Å ≤ λ ≤ 1780 Å interval with log gf ≥ 0.1). The ten lines with the largest gf values (0.77 ≤ log gf ≤ 1.10, the two strongest are Tc vλλ 1440.505,1163.237 Å) are labeled with their wavelengths.