THERMAL RELAXATION OF AG(111)

We present the results of an embedded-atom-method molecular-dynamics simulation of the thermal relaxation of Ag(111). Contrary to recent medium-energy ion-scattering experiments [P. Statiris et al., Phys. Rev. Lett. 72, 3574 (1994)], which find that a change in the sign of the surface relaxation takes place upon heating above 750 K (from contraction to expansion), we find the surface layer to relax inwards at all temperatures. The calculated mean-square amplitudes of vibration, on the other hand, agree quite well with experiment. The model, in addition, shows evidence of premelting at a temperature of about 1000 K. © 1994 The American Physical Society.