Atomic collective excitations in liquid lead

The atomic dynamics of liquid lead at the temperature $T=600\,$K has been simulated on the basis of the embedded atom model potential (the “embedded” atom model making it possible to effectively take into account the many-particle interactions) in order to study the mechanisms of formation of the atomic collective excitations. Spectra of the dynamic structure factor $S(k,\omega)$ and the spectral densities of the time correlation functions of the longitudinal $\widetilde{C}_L(k,\omega)$ and transverse $\widetilde{C}_T(k,\omega)$ currents have been calculated for the wavenumber region $0.11$ Å$^{-1}\leq k \leq 2.01$ Å$^{-1}$. It has been established that the dynamics of density fluctuations is characterized by two dispersion “acoustic-like” branches of the longitudinal and transverse polarization.