The IR and Raman intensities were derived from the partial dipole gradients and the partial polarizability gradients according to the scheme described by Dundas et al., where the IR intensity is reported in terms of the molar decadic attenuation coefficient ϵ and the Raman intensity is related to the absolute differential Raman cross sections σ ′ . The frequencies and normal modes were obtained from the eigenanalysis of the partial Hessian.