Collective Atomic Motions in Liquid Sodium

This is the authors' abstract. We don't add key points for this paper.

The self-consistent field method developed by Singwi et al. for the collective modes in classical liquids in the region of high-frequency large-wave-vector transfer has been employed to calculate the spectral function of longitudinal current–current correlations in liquid sodium at the melting point. It is found that in liquid sodium the presence of long-range Coulomb forces results into a particularly strong polarization field. The curves for longitudinal current–current correlations at fixed q's show strong peaks lying at different frequency (ωmax) in each case. From these ωmax(q) values a frequency wave-vector transfer dispersion curve is drawn for liquid sodium similar to the phonon dispersion curve in solid phase. Such a dispersion curve reflects pronounced collective excitations, and thus in liquid sodium the collective aspect plays a significant role in high-frequency large-wave-vector transfer region.