A b i n i t i o and embedded-atom-model simulation analysis of collective dynamics in liquid Fe at experimental high pressures

We compare extensive simulations and embedded-atom-model molecular dynamics for analysis of collective dynamics in liquid Fe at several experimental pressures and temperatures of 2200 and 2700 K [Y. Kuwayama , ]. Dynamic eigenmodes of the generalized Langevin equation were calculated based on simulation data and analyzed in a wide range of wave numbers with a focus on dispersion of collective excitations. We analyze the origin of positive dispersion of sound excitations in connection with contributions from different types of hydrodynamic and nonhydrodynamic fluctuations to the corresponding eigenvectors. Dispersion of collective excitations and adiabatic speed of sound, estimated from the simulation data at three pressures, is compared to the values obtained from the inelastic x-ray scattering experiments.