Brillouin neutron scattering of v-GeO2

The high-frequency dynamics of v-GeO2 was investigated by inelastic neutron scattering. Neutron experiments were carried out by exploiting both three-axis and time-of-flight techniques as most adequate to selectively access to a wider kinematics region or to higher-resolution characteristics. Experimental evidences of a highly dispersing inelastic peak, with an associated velocity of 3650 ms(-1), and an almost dispersionless inelastic structure allowed us to definitely confirm the propagating nature of the high-frequency excitations. The measured data were compared with the results of a molecular-dynamics simulation.