Molecular motions of benzene adsorbed in ZSM-5 zeolite: quasielastic neutron scattering study

We report dynamics of benzene molecules contained in the pores of HZSM-5 and CaZSM-5 zeolites as studied by the quasielastic neutron scattering technique at room temperature. Benzene molecules are found to undergo a six-fold jump rotation in both the zeolites. The residence time obtained is close to the residence time found in the case of solid benzene. The residence time of benzene in CaZSM-5 zeolite is found to be more than that of benzene in HZSM-5 zeolite. A Fourier-transform infrared study indicated a strong intermolecular interaction, which gives rise to a solid-like state of benzene in the pores of zeolites.