High-Resolution Photoelectron Spectroscopy of Cryogenically Cooled VO ₃ H ₂ –

High-resolution photoelectron spectra of cryogenically cooled VO₃H₂⁻ anions obtained with slow electron velocity-map imaging (cryo-SEVI) are reported. Comparison with DFT calculations shows that the spectra are from the cis-VO(OH)₂⁻ dissociative adduct. The same complex is formed through either the VO₂⁻ + H₂O or VO₃⁻ + H₂ pathways, with the latter yielding significantly more ions. The experiment yields an electron affinity of 1.857(1) eV and several vibrational frequencies for the neutral species. Comparisons to Franck-Condon (FC) simulations show good agreement with the experimental features, but there are several transitions that do not appear in the simulations. These features are assigned to FC-forbidden transitions involving nontotally symmetric vibrational modes and are attributed to Herzberg-Teller (HT) coupling with the excited C̃¹B₂ anion state. The results are compared to the previous (cryo-SEVI) study of the titania water-split adduct, TiO₃H₂⁻ to explore the role of the additional vanadium valence electron in the spectroscopy and chemistry of these adducts.