Electron spin resonance of an X-ray irradiated single crystal of disodium hydrogen arsenate, Na2HAsO4.7H2O

Abstract

X-ray irradiation of disodium hydrogen arsenate Na₂HAsO₄.7H₂O has been shown to produce a paramagnetic species exhibiting a quartet due to hyperfine interaction at the ⁷⁵As nucleus. The g-tensor and the hyperfine coupling have been found to be axially symmetric. A theoretical treatment is given which enables the experimental observations to be used to evaluate the hyperfine interaction tensor, the principal values of which are A = 2031·8 Mc/s and B=1581·6 Mc/s. The paramagnetic species has been identified as the ·AsO₃ ^2- radical anion with symmetry C _3v .