ESR studies of paramagnetic centres in irradiated Sr(ClO3)2single crystals

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Abstract
Paramagnetic centres produced by irradiation of Sr(ClO3)2 single crystals have been studied by electron spin resonance. The products of x- or delta -irradiation at 298K are ClO2 and O3- centres. ClO2 is trapped at six magnetically inequivalent sites in the crystal lattice, forming three pairs. The magnetic parameters for two of the pairs, that is, ClO2(B) and ClO2(C), are in close agreement with ClO2 centres reported in other systems; while the third pair, that is ClO2(A), has slightly different hyperfine parameters. The principal g-values of this centre (A) are gxx=1.9984, gyy=2.0170 and gzz=2.0142 and those of the A tensor are Axx=90.0 G, Ayy=-8.7 G and Azz=-5.0 G. The chlorine centres that are trapped at six magnetically inequivalent sites produced by radiation damage reveal hexagonal symmetry among themselves. UV or thermal bleaching (at 90 degrees C) removes all the chlorine centres, giving a single anisotropic line, trapped at two magnetically inequivalent sites with a gav=2.0092. This new centre is identified as an O3- centre.