The application of Mossbauer spectroscopy in investigating iron compounds in car exhaust

Mossbauer spectroscopy has been applied to analyse the iron compounds present in car exhausts. From the shapes of the Mossbauer spectra at room temperature it is inferred that iron appears basically as alpha -Fe2O3 in the form of ultra-fine particles, of approximately 120 AA diameter, in the superparamagnetic phase and also in ferromagnetic phase.