Electron Paramagnetic Resonance Study of the Radiation Damage Centers in Menadione Single Crystal

Abstract

The radiation damage centers in the Co-60-gamma rays irradiated menadione (2-methyl-1,4-naphthoquinone; Vitamin K-3; C11H8O2) single crystals were examined at 120 K by Electron Paramagnetic Resonance (EPR) spectroscopy. The presence of two radicals was detected in the compound. Both radicals are carbon centered radicals. Analysis of the EPR spectra of gamma-irradiated menadione single crystals along three different axes showed that the C(11)-H(19) bond of the compound was broken. It was determined that the unpaired electron located on the C(11) atom. The g values and the hyperfine structure constants of the radiation damage centers observed in menadione single crystal were obtained. Accuracy of experimental data was observed by simulation study.