Computer simulations of vibrational spectra and sound velocity in liquid cesium up to the critical point

Abstract The results of ‘phonon’-spectra computer simulations on the basis of the recursion method for liquid cesium for the whole temperature range up to the critical point are presented. The comparison of the experimental data and the calculation results allowed us to conclude that the method gives a precision that is sufficient for the quantitative calculation of the physical properties of melts. We establish that the dispersion curves, ω(k), used in analytical theories, in the case of liquid metal has the meaning of a average frequency of a spectrum of collective excitations at the given k value. The application of this method to liquid cesium at various temperatures has shown that at high temperatures there is a qualitative modification of the phonon spectrum that suggests a high localization of the vibration states of liquid metals. The results indicate the presence of a considerable number of highly bound clusters such as dimers, molecular ions or tetrahedrons in liquid metals at high temperatures.