Electron Spin Resonance Transitions involving Simultaneous Changes in Spin States of up to Three Neighbouring Protons

Abstract

OCCASIONALLY an electron spin resonance absorption line is accompanied by satellite lines of weak intensity. These satellite lines, arising from a change in spin state of a nearby nucleus concurrent with the change in spin state of the electron, were first observed in irradiated frozen acids¹. A theoretical explanation for these transitions has been given by Trammell et al.², who also predicted a second set of satellites corresponding to two neighbouring protons concurrently changing their spin state. Recently Snipes and Bernhard³ observed such satellite lines in γ-irradiated single crystals of barbituric acid dihydrate. We report here experimental evidence of a second and even a third set of satellites corresponding to two and three neighbouring protons simultaneously changing spin state.