A theoretical study of the influence of interaction between transition metal atoms and carbon monoxide on infrared and Raman intensities of the C-O stretching vibration.

The structures and the spectral properties of the transition metal M-CO complexes have been investigated by performing the calculation of the hybrid density functional theory approach. The calculated results show that for each M-CO complex the infrared intensity of the C-O stretching mode is significantly larger than that of the M-C stretching mode and the bending modes. The Raman scattering factor of the C-O stretching mode is the largest among three modes. Comparison of the calculated results indicates that the C-O modes of M-CO complexes, the metal atom of which belongs to the fourth periodic metals and the Cu group, have larger Raman scattering factors than those in the other M-CO complexes.