Lattice dynamics calculations and phonon dispersion measurements of zircon, ZrSiO4

Lattice dynamical calculations using a shell model are carried out for the geophysically important mineral zircon, ZrSiO4. The model parameters are ad justed so that the model satisfactorily reproduces the literature data on s tructure, elastic constants and optically active modes. Phonon dispersion r elations are measured on a single crystal using coherent-inelastic neutron scattering on the PRISMA spectromter at the UK ISIS facility. The one-phono n structure factors are calculated to preselect the Bragg points for the me asurements and to assign measured phonon signals to different branches. The phonon dispersion relations measured are in good agreement with the calcul ations.