The inelastic neutron scattering spectrum of commercial samples of industrially important zeolites ZSM-5 (Si/Al ratios: 25, 30, 80,and 280), Beta (Si/Al ratios: 25, 38, and 300) and Y (Si/Al ratios: 30, 60 and 80) will be measured, performing the first parametric study of zeolites investigating the effect of Si/Al ratio on the framework structure. The measurements will be performed both on the original ammonium form of the zeolite and on the catalytically active protonated form, post calcination . The results from the investigation will be used in conjunction with molecular simulations performed at University College London in order to gain an insight into the surrounding local structure and favourable configurations of the proton sites which give these materials their catalytic properties, and how the nature of these sites changes as the Si/Al ratio of the bulk framework is varied.