Energy transfer mechanisms on some ?-irradiated synthetic zeolite surfaces

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Abstract
The trapped paramagnetic centers in four γ-irradiated zeolites have been examined by esr spectroscopy. The centers in NaA, NaX and NaY are identified as trapped holes away from substituent Al− ions; in CaA, trapped holes adjacent to Al− ions. Electron scavengers added to the zeolites prior to the irradiation do not affect these centers, and no anion radicals are observed at 77°K. On the contrary, electron donors prevented the formation of these trapped holes and some radicals and cation radicals are produced, leading to the conclusion that there is energy transfer on the surfaces of the four zeolites tested, similar to the surface of silica under the same conditions. This hypothesis can be used to account for the radiolysis products of pentane and carbon dioxide on molecular sieves and silica gel.