Influence of Pt—Cl force constants on the Raman lineshapes in Pt35Cl/37Cl chains

The influence of the 35 Cl/37 Cl isotopic disorder of natural chlorine on the Raman and infrared lineshapes of the vibrational modes in PtCl chains was calculated as a function of the interionic force constants in a one‐dimensional model. It is shown that the fine structure of the Raman line is strongly dependent of the Pt3+σ‐Cl and Pt3‐σ‐Cl force constants, and so it can be used to estimate the charge disproportion σ. From the case of [Pt(en)2][Pt(en)2Cl2](ClO4)4 it appears that the description of the high‐wavenumber infrared line (v2) requires one to take into account interactions with more distantations. It is also shown that the intensity of the lowwavenumber infrared‐active mode (v3) is so weak that the corresponding line may have never been observed.