Mixing of Internal Modes of Different Molecular Symmetry in LiIO3

We present experimental data which show that there is a smooth and continuous frequency and polarization variation with phonon propagating directions in single-crystal LiI${\mathrm{O}}_3$, which implies a mixing of phonon symmetries at k=0 and continuous mixing of internal vibrational modes of the I${\mathrm{O}}_3^{-}$ion.