A new structural analysis of the Pt(111)-(1 x 1) surface by low energy electron diffraction gives an unexpected lattice parameter compression of 3.904Å with respect to the crystallographic value of 3.924Å; yielding a Pendry R-factor of 0.078. This implied a 0.5% contraction for both the in-plane lattice parameter, 2.761Å, and bulk vertical interplanar distances, 2.25Å, as compared with the crystallographic values of 2.775 and 2.265Å, respectively. The top-most surface layer exhibited an expansion of 0.9%, 2.285Å, and the second a contraction of 0.9%, 2.245Å. Deeper layers were bulk layers.

Surface and Bulk Reconstruction of Pt(111) 1 x 1. S.Gallego, C.Ocal, F.Soria: Surface Science, 1997, 377-379, 18-22