Microscopic Dynamics of Liquid Aluminum Oxide

Abstract

Collective excitations have been observed in liquid aluminum oxide at high temperatures by combining a containerless sample environment with inelastic x-ray scattering. The excitation spectra show a well-defined triplet peak structure at lower wave vectors Q (1 to 6 nanometers −1 ) and a single quasi-elastic peak at higher Q . The high- Q spectra are well described by kinetic theory. The low- Q spectra require a frequency-dependent viscosity and provide previously unknown experimental constraints on the behavior of liquids at the interface between atomistic and continuum theory.