Relaxations in the 1 x 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 x 2 translational sym metry, but a 1 x 3 form has also been seen. Between 1 x 2 and 1 x 3, a series of disordered structures has been recorded, which shows a slight preference for 1 x 5 periodicity. Under the preparation conditions used in this study, a stable 1 x 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 x 2 and 1 x 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. (C) 2004 Elsevier B.V. All rights reserved.