Neutron scattering function of vitreous and molten zinc chloride

The dynamics of vitreous and molten zinc chloride have been studied with inelastic neutron scattering at the Intense Pulsed Neutron Source at Argonne National Laboratory. The results are analyzed in terms of the scattering function S(Q, E) and the effective vibrational density of states G(E). The vibrational spectra of both glass and liquid are dominated by broad features centred at 15 and 35 meV which are identified with the F₂ modes of ZnCl₄^2- tetrahedra. The other two normal modes are not observed because of inadequate resolution and because of broadening and overlap resulting from coupling between tetrahedra. The energy widths of the scattering are lower than those predicted for independent particles over the entire Q range of the measurement, indicating strong binding of the ions to the network structure in both the glass and liquid.