NO32- centers in synthetic hydroxyapatite

The structure and properties of NO32− paramagnetic complexes formed by γ-rays and UV irradiation in synthetic hydroxyapatite have been investigated using EPR spectroscopy. The formation of NO32− centers under UV irradiation has been revealed for the first time. It has been found that NO32− complexes in synthetic hydroxyapatite form two types of paramagnetic centers. Models of the centers have been proposed, their EPR spectroscopy parameters have been determined, and the influence of thermal annealing has been investigated. As the microwave power increases, the inversion of the EPR spectra has been observed.