Determination of the first ionization potential of technetium

The first ionization potential (IP) of technetium (Tc) has been determined by evaluating Rydberg convergences toward the first ionization potential as well as toward two low-lying excited states of the singly charged Tc ion. The Rydberg states were excited and detected by applying multiphoton resonance ionization mass spectrometry (RIMS) on the long-lived isotope ⁹⁹ᵍTc using a three-color excitation scheme. The observed Rydberg convergences yield a result for the first ionization potential of Tc VIP(Tc)=7.119380(32) eV. This precise value for VIP(Tc) is somewhat lower than the so far published data of $7.23$ eV or $7.28$ eV, dating back to the 1950s.