Photoionization and energy-dependent photochemistry of hydrocarbons in ZSM5

Photostimulated processes involving unsaturated hydrocarbon molecules adsor bed in ZSM5 were investigated under oxygen-free conditions. The primary pro ducts of photoionization (radical cations) and neutral photochemistry (radi cals) were observed by EPR spectroscopy. Photoionization is a multiphoton p rocess over the wavelength range studied (248-600 nm). Radical products ind icate single-photon C-C bond dissociation and multiphoton C-H bond dissocia tion reactions of neutral excited states. The implications for applications of zeolites in photocatalysis are discussed.