These spectra represent a significant improvement over previous anion photoelectron spectroscopy studies. The improved resolution afforded by the cryo-SEVI method reveals not only the electronic transitions to the three lowest-lying states of NiO2 (features A1, C1, D1, respectively) previously observed, but also a manifold of transitions to vibrationally excited states of the neutral species. Peak assignments, electron binding energies (eBEs), as well as shifts from peak A1 are presented in Tables , while extracted experimental parameters are presented in Table .