Electron spin resonance of (CO2H)CH2-ĊH(CO2H) in succinic acid

Abstract

Electron spin resonance investigations on a γ-irradiated single crystal of succinic acid have confirmed and extended the findings of Heller and McConnell on the hyperfine couplings in the radical (CO₂H)ĊH-CH₂ (CO₂H). Complete coupling tensors, and the g tensor, are given in the table. These confirm that the radical has almost the same orientation as the unchanged molecules. The plane of the free radical carbon is twisted 5° from the original carbon skeleton plane and this leads to appreciable non-equivalence of the hydrogen atoms of the CH₂ group.