Relaxations in the 1×5 reconstruction of Pt(110)

Pt(110) is one of the most closely investigated metal surface structures because it displays a variety of “missing-row” reconstructions, which are only marginally stable. The ground state is usually found to have 1×2 translational symmetry, but a 1×3 form has also been seen. Between 1×2 and 1×3, a series of disordered structures has been recorded, which shows a slight preference for 1×5 periodicity. Under the preparation conditions used in this study, a stable 1×5 structure was found for Pt(110). Investigation by surface X-ray diffraction has led to a complete three-dimensional structure, which closely resembles an alternation of 1×2 and 1×3 unit cells. Pt(110) shows an interesting example of two “homometric” structures that are indistinguishable by diffraction, but are distinguishable by virtue of their subsurface relaxation pattern.