NUMERICAL-ANALYSIS OF EPR-SPECTRA OF COAL, MACERALS AND EXTRACTION PRODUCTS

The multi-component structure of the EPR spectra of Polish medium meta morphosed coal, its macerals and their pyridine extraction products we re analyzed. The best numerical approximation of the EPR spectra for e xinite, vitrinite and their extraction residues was obtained when two Lorentz and one Gauss curve were chosen for calculation. The EPR spect ra of inertinite and its residue are superposition of two Lorentz line s. The EPR spectra of the extracts are fitted by single Lorentz lines. Four groups of paramagnetic centres which give the EPR signals with d ifferent ranges of linewidths are present in the macerals and the extr action products. Paramagnetic centres with the narrow EPR lines are pr esent not only in inertinites, but also in exinites and vitrinites. Ea ch of the four types of paramagnetic centres is present in macromolecu lar and molecular part of the macerals. As was expected, four componen t lines were detected for the EPR spectra of the coal and its residue. Paramagnetic centres responsible for the broad lines are located on s tructures consisting of a few aromatic rings. Paramagnetic centres of large aromatic structures are responsible for the narrow lines.