Thermal expansion of Ag(111)

The contribution of surface vibrations to the thermal expansion of Ag(111) is analyzed at several levels of approximations. In the quasiharmonic scheme, the surface vibrational density of states, which may be represented fairly by modes at the high symmetry points in the surface Brillouin zone, do not lead to anomalously large thermal expansion, in accordance with results from molecular-dynamics simulations that give a good description of other anharmonic properties of Ag(111). We illustrate how an inadequate representation of the density of states can lead to erroneously large surface thermal expansion.