Calculating relative intensities for CH stretching polyads of CHI3 with ab initio dipole moment surface

Relative intensities of the Fermi resonance polyads involving CH stretching and bending vibrations for the CHI3 molecule are calculated with one- and two-dimensional dipole moment surfaces. These are obtained by the ab initio density functional method. The two-dimensional dipole moment surface reproduces the relative intra-polyad intensities quite well, indicating the importance of the bending vibrations in dipole moment surface and intensities calculations. The relative inter-polyad intensities are also predicted.