Nuclear resonant forward scattering (NFS) and nuclear inelastic scattering (NIS) of synchrotron radiation are fairly recent spectroscopic methods for the investigation of complexes containing Mossbauer-active transition metal ions. NFS, which can be
regarded as Mossbauer spectroscopy in the time domain, overcomes some limitations of conventional Mossbauer spectroscopy as has been demonstrated especially for bioinorganic compounds. NIS extends the energy range of conventional Mossbauer spectroscopy to the range of molecular vibrations. Since NIS is sensitive only to the mean-square displacement of Mossbauer nuclei it can be used as site-selective vibrational spectroscopy. It complements usefully comparable techniques such as IR or Raman spectroscopy. Examples are given for applications to spin crossover complexes, nitroprusside compounds, heme model complexes and myoglobin.
