ESR studies of Ba(BrO<inf>3</inf>)<inf>2</inf>· H<inf>2</inf>O single crystals γ-irradiated at 300 K and 77 K

The paramagnetic defect centers observed in Ba(BrO3)2· H2O single crystals γ-irradiated at 300 K were identified as O-3 and O-. There are two other chemically inequivalent O- centers which could be observed at 77 K. O-3 centers do not exhibit any superhyperfine (SHF) interaction, but all the O- centers show SHF interaction due to the protons of waters of hydration. The O-3 center observed in the γ-irradiated dehydrated poly-crystalline samples was found to be undergoing rapid molecular rotation. After γ-irradiation at 77 K, a complex paramagnetic center identified as BrO2-3H2O was observed. The stabilities of these centers and their orientations in the present lattice are discussed. The present results also indicate differences in the nature of radiation damage mechanisms and the possible hydrogen bondings in the isostructural Ba(BrO3)2· H2O, Ba(ClO3)2 · H2O and Sr(BrO3)2 · H2O compounds. © 1984.