The transverse acoustic excitation modes were detected by inelastic x-ray scattering in liquid Ga in the Q range above 9 nm-1 although liquid Ga is mostly described by a hard-sphere liquid. An ab initio molecular dynamics simulation clearly supports this finding. From the detailed analysis for the S(Q,ω) spectra with a good statistic quality, the lifetime of 0.5 ps and the propagating length of 0.4-0.5 nm can be estimated for the transverse acoustic phonon modes, which may correspond the lifetime and size of cages formed instantaneously in liquid Ga. The microscopic Poisson's ratio estimated from the dynamic velocities of sound is 0.42, indicating a rubber-like soft elastic property of the cages.
ASJC Scopus subject areas
- Materials Science(all)
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry