Experimental Confirmation of the Universal Law for the VibrationalDensity of States of Liquids

An analytical model describing the vibrational density of states (VDOS) ofliquids has long been elusive, owing to the complexities of liquid dynamics. Nevertheless,Zaccone and Baggioli have recently developed such a model which was proposed to be theuniversal law for the vibrational density of states of liquids. Distinct from the Debye law,g(omega)proportional to omega 2, for solids, the universal law for liquids reveals a linear relationship,g(omega)proportional to omega, in the low-energy region. We have confirmed this universal law with experimental VDOS measured byinelastic neutron scattering on real liquid systems including water, liquid metal, and polymerliquids, and have applied this model to extract the effective relaxation rate for the short timedynamics for each liquid. The model has also been further evaluated in the prediction of thespecific heat with comparison to existing experimental data as well as with values obtained bydifferent approaches.

Automated summary

This article presents an analytical model for describing the vibrational density of states of liquids, which is proposed as the universal law for liquids. The authors have confirmed this universal law through experimental measurements and applied the model to extract the effective relaxation rate for each liquid's short-time dynamics.