The surface phonon dispersion relations were calculated for the platinum and copper (100) faces using a model developed by Castiel et alia (1976). Relaxation of the surface force constant led to a lowering of the phonon frequencies which could vanish for the smallest phonon wavelengths (soft phonons). It was shown that this mechanism could not yield a copper surface rearrangement, but could produce a fifth order reconstruction in the case of platinum; in agreement with experimental results.

Soft Surface Phonons and Reconstruction - Platinum and Copper (100) Faces. J.G.Sanz, G.Armand: Surface Science, 1982, 118[1-2], 291-302