SPECTRUM DECOMPOSITION THROUGH MAXIMUM-LIKELIHOOD COMMON FACTOR-ANALYSIS OF THE EPR-SPECTRA OF NA-DEGREES-C( CONTAINING CARBONATED APATITESDRIED AT 400)

X-irradiated carbonated apatites precipitated from aqueous solutions a nd dried at 400-degrees-C until constant weight are investigated with electron paramagnetic resonance (EPR). The carbonate content of the sa mples studied ranges from 8.12 to 21.0 wt%. The observed multicomponen t EPR spectra are analyzed with maximum likelihood common factor analy sis (MLCFA), a multivariate statistical technique. Once the correct nu mber of constituents are determined and the factor spectra estimated b y MLCFA, a minimization procedure is performed in order to transform t he abstract factor spectra linearly into an equal number of real EPR p owder spectra. The spin hamiltonian parameters of the component spectr a thus obtained are used to characterize and identify the different pa ramagnetic radicals. A comparison with values from the literature is m ade. A spectrum decomposition study of all the observed multicomponent EPR spectra in terms of the isolated constituents is successfully per formed as a function of the carbonate content of the samples.