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Oxygen-adsorption induced reconstruction of Cu(110) studied by high energy ion scattering
A375 Surface Science 133 (1983) 443-452 North-Holland Publishing C o m p a n y
443
DETERMINATION OF, H Y D R O G E N ATOM BINDING SITES ON Ru(001) BY HREELS M.A. BARTEAU *, J.Q. B R O U G H T O N and D. M E N Z E L Physik-Department E20, Technische Universitdtt Miinehen, D-8046 Garehing bei M#nchen, Fed. Rep. of Germarzv Received 4 March 1983; accepted for publication 28 June 1983 High resolution electron energy loss spectra of hydrogen adsorbed on Ru(001) have been obtained. At saturation, two losses at 105 and 138 meV are found (67 and 103 meV for deuterium); the lower energy peak shifts with coverage. Measurements away from the specular direction suggest that the main loss mechanism is impact scattering. It is concluded that H on Ru(001) sits in the two types of threefold hollow sites, and the two losses are due to the symmetric out-of-plane and the asymmetric in-plane vibrations, as has been observed for H on N i ( l l l ) and P t ( l l l ) by other workers. The energy change of the lower loss may be caused by the difference between H in fcc and hcp sites whose relative occupation changes with coverage.
Surface Science 133 (1983) 453-468 North-Holland Publishing C o m p a n y
453
O X Y G E N - A D S O R P T I O N INDUCED RECONSTRUCTION OF Cu(110) S T U D I E D BY HIGH ENERGY ION SCATTERING R. F E I D E N H A N S ' L and I. S T E N S G A A R D Institute of Pt~ysics, University of Aarhus, DK-8000 Aarhus C, Denmark Received 15 March 1983; accepted for publication 27 June 1983 The adsorption of oxygen on Cu(110) has been studied by High Energy Ion Scattering (HEIS). Analysis of the (2 x 1)-O structure indicated an absolute oxygen coverage of 0.51 -+ 0.06 monolayer. Good agreement with experimental data was obtained for a buckled (110) surface model, in which every second [0011 surface row is displaced outwards by 0.27__+0.05 ,& from its bulk-like position, with the remaining [0011 surface rows shifted insignificantly inwards by 0.02_+0.03 ~. and the second layer displaced outwards by 0.06 + 0.03 ,~. The c(6 x 2)-0 structure was shown to involve lateral displacement components ~- 0.3 ,~ for the first monolayer atoms.
443
DETERMINATION OF, H Y D R O G E N ATOM BINDING SITES ON Ru(001) BY HREELS M.A. BARTEAU *, J.Q. B R O U G H T O N and D. M E N Z E L Physik-Department E20, Technische Universitdtt Miinehen, D-8046 Garehing bei M#nchen, Fed. Rep. of Germarzv Received 4 March 1983; accepted for publication 28 June 1983 High resolution electron energy loss spectra of hydrogen adsorbed on Ru(001) have been obtained. At saturation, two losses at 105 and 138 meV are found (67 and 103 meV for deuterium); the lower energy peak shifts with coverage. Measurements away from the specular direction suggest that the main loss mechanism is impact scattering. It is concluded that H on Ru(001) sits in the two types of threefold hollow sites, and the two losses are due to the symmetric out-of-plane and the asymmetric in-plane vibrations, as has been observed for H on N i ( l l l ) and P t ( l l l ) by other workers. The energy change of the lower loss may be caused by the difference between H in fcc and hcp sites whose relative occupation changes with coverage.
Surface Science 133 (1983) 453-468 North-Holland Publishing C o m p a n y
453
O X Y G E N - A D S O R P T I O N INDUCED RECONSTRUCTION OF Cu(110) S T U D I E D BY HIGH ENERGY ION SCATTERING R. F E I D E N H A N S ' L and I. S T E N S G A A R D Institute of Pt~ysics, University of Aarhus, DK-8000 Aarhus C, Denmark Received 15 March 1983; accepted for publication 27 June 1983 The adsorption of oxygen on Cu(110) has been studied by High Energy Ion Scattering (HEIS). Analysis of the (2 x 1)-O structure indicated an absolute oxygen coverage of 0.51 -+ 0.06 monolayer. Good agreement with experimental data was obtained for a buckled (110) surface model, in which every second [0011 surface row is displaced outwards by 0.27__+0.05 ,& from its bulk-like position, with the remaining [0011 surface rows shifted insignificantly inwards by 0.02_+0.03 ~. and the second layer displaced outwards by 0.06 + 0.03 ,~. The c(6 x 2)-0 structure was shown to involve lateral displacement components ~- 0.3 ,~ for the first monolayer atoms.