Exact interaction matrices were reported for a B-stabilized oxygenic-hole centre in X-irradiated zircon, as derived from X-band electron paramagnetic resonance measurements that were performed at about 15K. The presence of B was clearly identified via the observation and spin-Hamiltonian analysis of superhyperfine structures from both naturally occurring B isotopes. Each of the parameter matrices indicated that the centre, [BO4]0, had point-group symmetry, m(Cs). This was common for hole centres in zircon, where the hole centre was trapped on an O atom within one of the crystal mirror planes. An analysis of the principal directions of these matrices indicated that the B atom resided in a Si position which neighboured the oxygenic electron vacancy.

15K EPR of an Oxygen-Hole Boron Centre, [BO4]0, in X-Irradiated Zircon. C.J.Walsby, N.S.Lees, W.C.Tennant, R.F.C.Claridge: Journal of Physics - Condensed Matter, 2000, 12[7], 1441-50