Trap-to-trap hole transfer studied by radiolysis/EPR. Radical cations in freon and zeolite matrices

Electron paramagnetic resonance (EPR) spectroscopy was used to assess the positive charge distribution in irradiated solid samples containing mixtures of donor molecules. The relative trap populations were determined from the EPR intensities of the respective radical cations of the olefinic donors. The occurrence of trap-to-trap hole transfer was examined as a function of the donor pair, donor concentration, and matrix. Three matrices were studied: CF3CCl3, CFCl3, and ZSM5 zeolite. The concentration dependence of the final charge distributions in some cases reflected the occurrence of resonant charge transfer. Surprising differences between CF3CCl3 and CFCl3 are explained by differences in matrix chemistry. The radiolysis/EPR technique applied to double-loaded zeolites serves as a method of probing the intracrystalline adsorption distributions and mobilities of guest species in zeolites.