The inelastic neutron scattering (INS) spectrum of polycrystalline Cs 2[B 12H 12] is assigned through 1200 cm -1 on the basis of aqueous and solid-state Raman/IR measurements and normal mode analyses from solid-state density functional theory. The Cs + cations are responsible for frequency shifts of the internal cage vibrational modes and I h cage mode splittings due to the crystal T h site symmetry. These changes to the [B 12H 12] 2- molecular modes make isolated-molecule calculations inadequate for use in complete assignments. Solid-state calculations reveal that 30/40 cm -1 shifts of T g/H g molecular modes are responsible for structure in the INS spectrum unobserved by optical methods or in aqueous solutions.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry