Field ion microscopy study of 1×2 reconstruction on Pt surfaces

With the use of field ion microscopy we have investigated an atomic structure of a 1×2 reconstruction of a Pt(110) and a Pt(331) crystallographic planes. For the Pt(110), a transition from a (1×1) phase into the (1×2) missing-row structure is observed upon annealing treatment at 450 K which is interpreted in terms of jumping or descending atom motions. For the Pt (331), a similar transition takes place upon heating at 600 K, and the atomic arrangement in two top 1×2 layers is compatible with the so called saw-tooth model. We propose a new structural model for the Pt (331)-(1×2) reconstruction.