Revisiting the electron affinity of selenium

The electron affinity (EA) of atomic selenium, previously established as 16 297.276(9) cm-1 based on the laser photodetachment microscopy (LPM) measurements in 2012, exhibited a significant deviation from other earlier experimental values, yet it remained the accepted reference standard for over a decade. In this letter, we re-examined the EA of Se using the slow-electron velocity-map imaging method and revealed a substantial deviation in the LPM result. Measurements for the different isotopes of Se and the energy-level splitting of the neutral Se atom's 3P2-3P1 further verified the accuracy and robustness of our SEVI method. Based on this experimental evidence, we recommended a revised EA(Se) value of 16 297.78(4) cm-1, which is in excellent agreement with the previous laser photodetachment threshold experimental results.