The observation of the longitudinal wave velocity in a model supercooled liquid

Abstract

We have improved the non-equilibrium molecular dynamics measurement for the longitudinal wave (LW) velocity (the speed of sound) and have applied it to a model system in 2D and 3D. The LW velocity at temperature of the glass or supercooled liquid state reaches the range of in the 2D system and in the 3D system, with a gradual increase with increasing temperature under the isochoric and adiabatic conditions. In our previous paper [4] we analysed that the cooperative motion in intermediate time and length scales propagates with a speed depending on temperature and found that its dependency is opposed to that of the LWs. It suggests that the cooperative motion spreads over the system in a different way of sound.

Keywords::

• generate the longitudinal wave
• longitudinal wave velocity
• molecular dynamics simulation
• temperature dependence of wave velocity
• propagation velocity of a cooperative motion (correlated motion)

Acknowledgements

This work has been supported by JSPS KAKENHI, grant number 24654126.