Effect of host structure on the rotational motion of adsorbed hydrocarbon has been investigated using molecular dynamics (MD) simulation technique. MD simulations have been carried out on propylene sorbed in Na-Y (having spherical cages), and ZSM-5 (consists of interconnecting channel network) zeolites. Librational motion of
propylene molecule was found to be present in ZSM-5 zeolite but was absent in case of Na-Y zeolite. While diffusing inside the ZSM-5 zeolite, propylene molecules prefer its orientation along the channel direction while no such orientational ordering is found in Na-Y zeolite.