Low-frequency modes of ferrocene in zeolite Y

Using the position of ferrocene in zeolite Y as found from diffraction, we calculate the vibration modes of the ferrocene molecule as a whole, and the internal rotation of the ferrocene C5H5 rings with respect to each other of a ferrocene molecule in a Y-type zeolite using density functional theory. We compare our computational results with inelastic neutron scattering. We are able to identify two translational modes. The other modes lie at higher energies and are overlaid by motions arising from the flexibility of the zeolite framework.