The cryo-SEVI spectra of the bare anions TiO2ˉ and ZrO2ˉ are very simple, each showing short progressions in the totally symmetric stretch and bend modes. The corresponding spectra of TiO2ˉH2O and ZrO2ˉH2O shown in Figures and, respectively, are considerably more complex and differ substantially from one another. The overview TiO2ˉH2O spectrum (in blue) has a pronounced progression (A1, A3, A7, A11) with a characteristic peak spacing of 678 cm -1 , along with multiple smaller features. Higher resolution spectra (in black) reveal an additional series of peaks B1-B11 that are not evident in the overview spectrum. Moreover, the photoelectron angular distributions (PADs) for the A and B peaks are quite distinct; the anisotropy parameter  is around 1.5 for the A peaks and 0 for the B peaks. The ZrO2ˉH2O spectrum is much more congested, and there are several doublets (B/C, O/P, etc)