Surface and bulk reconstruction of Pt(111) 1x1

A new structural analysis of the Pt(lll) 1 x 1 surface by low energy electron diffraction gives an unexpected lattice parameter compression of a(0)=3.904 Angstrom with respect to the crystallographic value of 3.924 A. yielding a Pendry R-factor of 0.078. This implies a 0.5% contraction for both the in-plane lattice parameter, a(p)=2.761 Angstrom, and bulk vertical interplanar distances, d(b)=2.25 Angstrom, as compared to the crystallographic values of 2.775 and 2.265 Angstrom, respectively. The topmost surface layer exhibits an expansion of 0.9%, 2.285 Angstrom, and the second a contraction of 0.9%, 2.245 Angstrom. Deeper layers are bulk layers.