Generalized collective modes in liquid Cs near the melting point

The dynamical properties of liquid caesium near the melting point are investigated within the generalized collective-modes approach in a Markovian approximation. The generalized thermodynamic quantities and spectra of collective modes have been obtained for the five-variables description of longitudinal fluctuations. As the basis variables, three conserved and two nonconserved quantities have been used: the number density, longitudinal momentum, and energy density; and the first time derivatives of the longitudinal momentum and the energy density. All of the static and dynamic correlation functions were calculated directly from molecular dynamics simulations for 500 particles over 165 000 time steps, avoiding any fitting parameters. A comparison with the experimental data and results of previous molecular dynamics simulations is made.