PARAMAGNETIC ABSORPTION OF SINGLE CRYSTALS OF SUCCINIC ACID IRRADIATED AT LOW TEMPERATURE.

Electron spin resonance absorption was observed in single crystals of (–CH2–COOH)2, (–CH2–;COOD)2, and (–CH2–13COOH)2 irradiated at 77°K. The principal paramagnetic species observed at low temperature has an unpaired electron in a 2pπ orbital on the carbon atom of the carboxyl group. It is probably ionized succinic acid with the oxygen of the carboxyl group carrying a negative charge.