High-resolution photoelectron spectroscopy of cryogenically cooled TiO2CH3OH−: An investigation of methanol splitting by TiO2−/0

High-resolution photoelectron spectra of cryogenically cooled TiO2CH3OH− anions obtained with slow electron velocity-map imaging are reported and used to explore the reactions of TiO2−/0 with methanol. The highly structured spectra were compared with results from DFT calculations to determine the dominant structure to be cis-CH3OTi(O)OH−, a dissociative adduct in which CH3OH is split by TiO2−. The experiment yields an electron affinity of 1.2152(7) eV for TiO2CH3OH as well as several vibrational frequencies for the neutral species. Comparison to Franck-Condon (FC) simulations shows that while most experimental features appear in the simulations, several are not and are assigned to FC-forbidden transitions involving non-totally symmetric vibrational modes. The FC-allowed and forbidden transitions also exhibit different photoelectron angular distributions. The FC-forbidden transitions are attributed to Herzberg-Teller (HT) coupling with the Ã2A″ excited state of the anion. The results are compared to previous cryogenic slow electron velocity-map imaging (cryo-SE-VI) studies of bare TiO2− and the water-split adduct TiO3H2−.