Paramagnetic resonance in irradiated Sr(NO3)2 single crystal

Abstract

Paramagnetic resonance absorption of centres with spin 1/2 centered aboutg=2 is reported in gamma-irradiated single crystals of Sr(NO3)2. At room temperature four centres are detected which appear to exhibit axial symmetry about the [111] crystal direction. Two of the observed centres have a resolved hyperfine structure of N14. This hyperfine structure and axial symmetry of the centres indicate that they could be irradiation products of the nitrate ion. To find the number of trapped electrons, a simplified calculation of the molecular orbitals of planar and pyramidal NO3 is carried out. Centres with a resolved hyperfine structure are then identified as pyramidal NO 3 − and a NO2 molecule rotating about the [111] direction. Two centres without hyperfine structure are not identified exactly.