1H and 2D electron nuclear double resonance (ENDOR) and electron spin echo envelope modulation (ESEEM) investigations on γ-irradiated betaine arsenate

Abstract Electron spin resonance, electron nuclear double resonance and electron spin echo envelope modulation measurements were performed on γ-irradiated betaine arsenate single crystals. The investigations revealed that two radicals, Ṅ(CH 3 ) 3 and (CH 3 ) 3 N + ĊHCOO − , are formed by the γ-irradiation at room temperature. The concentration of both radicals decays in time with a time constant of a few days. In deuterated betaine arsenate the protons of the CH 2 group are partially replaced by deuterons. The 14 N hyperfine coupling tensor of the Ṅ(CH 3 ) 3 radical as well as the 1 H, 2 D hyperfine coupling tensor and the 2 D quadrupole tensor of the (CH 3 ) 3 N + ĊHCOO − ((CH 3 ) 3 N + ĊDCOO − ) radicals were determined.