ELECTRON-SPIN RESONANCE STUDY OF COAL BY LINE-WIDTH AND LINE-SHAPE ANALYSIS

ESR spectra were obtained for coal samples of various ranks. New parameters for line width which are directly obtainable from first derivative curve of ESR spectrum and invariant with line shape are investigated. Plots of those parameters against carbon content show a positive correlation. The line width phenomena can be explained by the formation of larger polynuclear, condensed aromatic ring systems in high-ranking coals using the theory developed by Weiss and Anderson of exchange narrowing in paramagnetic resonance. The positive correlation of line width and spins-per-gram with ranks is consistent with the hypotheses of Austin and of Ingram. Line shape parameters may be used to characterize coals and their derivatives. © 1979, American Chemical Society. All rights reserved.