Mossbauer parameters of ordinary chondrites influenced by the fit accuracy of the troilite component: an example of Chelyabinsk LL5 meteorite

The influence of the fit accuracy of the troilite component in the Mossbauer spectra of ordinary chondrites on the parameters obtained for other spectral components was evaluated using the Mossbauer spectrum of Chelyabinsk LL5 meteorite fragment with light lithology as a typical example. It was shown that with respect to the application of a usual sextet component where quadrupole interaction is taken into account in the first-order perturbation limit, substantial improvement of the spectrum fit can be achieved either by using the full Hamiltonian description of the troilite component or by its formal approximation with the superposition of three symmetric doublet components. Parameter values obtained for the main spectral components related to olivine and pyroxene were not sensitive to the fit of troilite component while parameters of the minor spectral components depended on the way of troilite component fitting.