First-principles screening calculation of the surface-phonon dispersion curves at the (001) surface of sodium

A self-consistent nonperturbative screening calculation of the surface-phonon dispersion curves has been carried out for the Na(001) surface. The Bloch states were caluclated by self-consistently solving the Kohn-Sham equations in the local-density approximation. From the Bloch states, the static electronic polarizability and density response function were obtained and used to calculate the surface-phonon dispersion curves. The changes in interatomic force constants at the surface are discussed, as are the effects of three-body interactions.