Dynamics of 1,3-butadiene adsorbed in Na-Y zeolite: a molecular dynamics simulation study.

Here we report dynamics of 1,3-butadiene molecules adsorbed in Na-Y zeolite as studied using molecular dynamics (MD) simulations. The results showed that the translational motion of the guest molecule exists in three different time scales one of which matches well with the quasielastic neutron scattering (QENS) measurement reported earlier. The translational motion in the component, which has been measured by QENS, is found to occur through discrete jumps, in agreement with the analysis of the experiments. The diffusion coefficients obtained from the correlation functions are compared to those obtained earlier for other hydrocarbons in Na-Y zeolite from MD simulation studies. The diffusion of 1,3-butadiene is found to be slower than that of acetylene but faster than that of propane. The rotational motion is found to be isotropic in nature. Rotational diffusion coefficient of 1,3-butadiene is found to be smaller than that of propane in Na-Y as expected due to the larger inertia of the former.