Hyperfine Structure in the OD ESR Spectra of Recombining Charge Pairs in Doped Polyethylene Matrices

The hyperfine structure has been resolved in the optically detected electron spin resonance (OD ESR) spectra of radical ion pairs generated by ionizing radiation at a low dopant concentration in a solid polyethylene matrix at room temperature. The different organic molecules that can capture electrons and holes were used as the dopants. The spin-lattice relaxation times T₁ for radical ions of dopants were estimated to be tens of microseconds. The temperature dependence of OD ESR signal intensity indicates the diffusion-assisted mechanism of recombination of radical ion pairs in polyethylene.