Interaction of Charged Particles and Atoms with Surfaces · K - Nb

This chapter illustrates surface phonon dispersion curves for KBr(001), KCl(001), LiF(001), MgO(001), Mo(001), NaCl(001), NaF(001), NaI(001) and Nb (001). The He-LiF(001) potential, He-NaCl(100) potential and He-NaF potential as function of the distance z from the center of the first surface ion are illustrated. A structural phase transition in Mo(001) is driven by a phonon mode softening at the zone boundary. This soft phonon mode continues toward the center of the Brillouin zone and mixes with the Rayleigh phonon in an avoided crossing.