ESR study of radiation-induced organic radicals in CaCO3

Radiation-induced organic radicals in CaCO3 doped with γ-aminobutyric acid and glycine, and Li2CO3 with adsorbed glycine were investigated by electron spin resonance. Isopropyl radicals occurred in CaCO3 doped with γ-aminobutyric acid. A signal at g = 2.0046 exhibiting interaction with a proton, a nitrogen and another proton was detected in glycine-doped CaCO3. The signal shows strong anisotropy of interaction with the first proton. The signal was also found in Li2CO3 with adsorbed glycine. The result revealed that amino acid molecules are on the surface of CaCO3.