Temperature Dependence of Surface Plasmon on Ag(001)

We report on high-resolution electron-energy-loss measurements of surface-plasmon losses on Ag(001) performed for crystal temperatures T in the range 100-400 K. Both the surface-plasmon frequency and linewidth are found to depend on T. The surface-plasmon frequency decreases with increasing T, nearly independently of wave vector; the linewidth increases by 7 x 10(-5) eV/K. The shift in energy is explained by the thermal expansion of the crystal, while the linewidth is influenced by the surface-plasmon-phonon interaction