EPR HFS SPECTRAL CHARACTERISTICS OF MN2+ IMPURITY IONS IN ARGONNE ANDALBERTA COALS

A new, more comprehensive study of the 9 and 33 GHz CW e.p.r. Mn2+ imp urity ion spectral characteristics of the eight Argonne premium coals and two Alberta h.v. bituminous coals is reported. These characteristi cs include the HFS a(1) relative amplitude, linewidth and lineshape as well as a more accurate and reliable determination of the g-value, th e HFS parameter A and the c(0)(2) and c(0)(4) ZFS parameters for powde red coal samples from the Delta M = +/-1, am = 0 central and weak non- central transitions using the spin Hamiltonian diagonalization spectra l simulation method of analysis. The six Mn2+ Delta m = 0 HFS central transitions observed in coal samples do not have two component resonan ces, unlike those for Mn2+ in polycrystalline calcite, which is attrib uted to lineshape broadening. However, the a(1) amplitude and linewidt h variation for the six Mn2+ HFS central transitions observed in each of the coal samples studied is consistent with that observed in polycr ystalline calcite. The consistency of the al amplitude and linewidth a nalysis as well as of the improved values of the e.p.r. spectral param eters for Mn2+ impurity ions in calcite and coal provides more conclus ive confirmation that the e.p.r. spectrum of Mn2+ originates from the calcite mineral component of coal.