Neutron scattering and computer simulation studies of ice dynamics

In this article we describe a range of simulations (lattice dynamics and molecular dynamics) of the inelastic incoherent neutron scattering spectra of ices (normal ice, ice II and ice VIII). These simulations use a variety of different intermolecular potentials from simple classic pair-wise (rigid and non-rigid molecule) potentials to sophisticated polarisable potentials. It was found that MCY makes stretching and bending interactions too weak while others do them well. We demonstrate that in order to reproduce the measured neutron spectrum, greater anisotropy (or orientational variation) is required than these potentials presently provide.