VIBRATIONAL ANALYSIS AND RESONANCE RAMAN-SPECTRA OF POLYCRYSTALLINE AND MATRIX-ISOLATED [CPFE(CO)(2)](2)

Polycrystalline and matrix-isolated trans-[CpFe(CO)(2)](2) (1) with Cp =eta(5)-C5H5, were examined using Raman and resonance Raman spectrosco py. The spectra recorded with different excitation wavelengths between 450 and 650 nm are described and discussed. Splitting of the nu(CO) b ands has been observed and interpreted by weak intermolecular forces w ithin the crystals and confirmed by a factor group analysis. The assig nments of the stretching modes have been confirmed by means of a norma l coordinate analysis (NCA) of the [LFe(CO)(2)](2)(L=point mass of Cp) fragment. The difficulties for an NCA using a simplified model are di scussed.