FC analysis of the ZrO(OH)2ˉ spectrum revealed two major differences that explain why its appearance is so different from the TiO(OH)2ˉ spectrum. First, as mentioned above, the anion and neutral Zr complexes are non-planar with different dihedral angles. Hence, a progression in the low frequency umbrella mode (12) of the neutral is FC allowed, as opposed to being only vibronically allowed as was the case in the TiO(OH)2ˉ spectrum, leading to many more closely spaced peaks in the ZrO(OH)2ˉ