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Adsorbate-induced structure transitions at the reconstructed Pt(100) surface
A387 Surface Science 287/288 (1993) 330-335 North-Holland
Adsorbate-induced structure transitions at the reconstructed Pt(lO0) surface J. Radnik, F. Gitmans, B. Pennemann, K. Oster and K. Wandelt Institut fiir Physikalische und Theoretische Chemie, Universitiit Bonn, Wegelerstrasse 12, 5300 Bonn 1, Germany Received 1 September 1992; accepted for publication 24 November 1992 The perfection of the Pt(100)(1 × 1) surface depends on the adsorbate used for lifting the hexagonal reconstruction of this surface. It is generally claimed that H E adsorption at temperatures >I 100 K leads to a poorly ordered, only "(1 x D-like" Pt(100) surface which together with desorption of the most strongly bound hydrogen state reconstructs again at 375 K. In turn, NO adsorption at room temperature followed by mild annealing is always reported to produce a more perfect Pt(100)(1 × 1) surface. In the present work we have reproduced these findings using LEED, TDS, work function measurements (Atb) and photoemission of adsorbed xenon (PAX). But more importantly we also describe a procedure to prepare a perfect Pt(100)(1 x 1) surface using only hydrogen, which has the same properties as the NO-prepared surface.
Surface Science 287/288 (1993) 336-339 North-Holland
Metal adatom induced corrugation of Cu(O01) Wei Li and Gianfranco Vidali Department of Physics, Syracuse University, Syracuse, NY 13244, USA Received 24 August 1992; accepted for publication 7 October 1992 We report the discovery of a metal adatom induced corrugation of Cu(001) as probed by atom beam scattering (ABS). At Pb or Bi coverages of 0.05 (fraction of Cu layer), and while a (1 X 1) LEED pattern is still observed, the ABS diffraction pattern from uncovered Cu(001) areas has changed considerably from that of clean Cu(001). We show that these uncovered areas have become up to ten times more corrugated than the clean Cu(001). We performed several carefully designed experiments to test whether our data could be interpreted as a result of scattering from adsorbate islands or from a lattice of randomly occupied sites. Instead, we ascribe the nature of this metal adatom induced corrugation to the redistribution of the Cu(001) surface charge density due to the adsorption of Pb or Bi atoms. No effect is seen following adsorption of weakly chemisorbed adatoms, such as Hg. A model consistent with all our observations is presented.
Surface Science 287/288 (1993) 340-345 North-Holland
Diffractive scattering of a helium molecular beam from a Ba monatomic layer on a W(110) surface Tatsuya Miyake and Shigehiko Yamamoto Advance Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-03, Japan Received 27 July 1992; accepted for publication 24 November 1992 The detailed two-dimensional ordered structures of a monatomic layer of barium (barium oxide) on a W(llO) surface has been investigated by using a molecular beam scattering technique which utilizes a high brightness helium supersonic beam with high coherence. We have successfully obtained, for the first time, diffractive scattering of a helium molecular beam from an ordered structure on the W(llO) surface covered with a sub-monatomic layer of barium (barium oxide).
Adsorbate-induced structure transitions at the reconstructed Pt(lO0) surface J. Radnik, F. Gitmans, B. Pennemann, K. Oster and K. Wandelt Institut fiir Physikalische und Theoretische Chemie, Universitiit Bonn, Wegelerstrasse 12, 5300 Bonn 1, Germany Received 1 September 1992; accepted for publication 24 November 1992 The perfection of the Pt(100)(1 × 1) surface depends on the adsorbate used for lifting the hexagonal reconstruction of this surface. It is generally claimed that H E adsorption at temperatures >I 100 K leads to a poorly ordered, only "(1 x D-like" Pt(100) surface which together with desorption of the most strongly bound hydrogen state reconstructs again at 375 K. In turn, NO adsorption at room temperature followed by mild annealing is always reported to produce a more perfect Pt(100)(1 × 1) surface. In the present work we have reproduced these findings using LEED, TDS, work function measurements (Atb) and photoemission of adsorbed xenon (PAX). But more importantly we also describe a procedure to prepare a perfect Pt(100)(1 x 1) surface using only hydrogen, which has the same properties as the NO-prepared surface.
Surface Science 287/288 (1993) 336-339 North-Holland
Metal adatom induced corrugation of Cu(O01) Wei Li and Gianfranco Vidali Department of Physics, Syracuse University, Syracuse, NY 13244, USA Received 24 August 1992; accepted for publication 7 October 1992 We report the discovery of a metal adatom induced corrugation of Cu(001) as probed by atom beam scattering (ABS). At Pb or Bi coverages of 0.05 (fraction of Cu layer), and while a (1 X 1) LEED pattern is still observed, the ABS diffraction pattern from uncovered Cu(001) areas has changed considerably from that of clean Cu(001). We show that these uncovered areas have become up to ten times more corrugated than the clean Cu(001). We performed several carefully designed experiments to test whether our data could be interpreted as a result of scattering from adsorbate islands or from a lattice of randomly occupied sites. Instead, we ascribe the nature of this metal adatom induced corrugation to the redistribution of the Cu(001) surface charge density due to the adsorption of Pb or Bi atoms. No effect is seen following adsorption of weakly chemisorbed adatoms, such as Hg. A model consistent with all our observations is presented.
Surface Science 287/288 (1993) 340-345 North-Holland
Diffractive scattering of a helium molecular beam from a Ba monatomic layer on a W(110) surface Tatsuya Miyake and Shigehiko Yamamoto Advance Research Laboratory, Hitachi, Ltd., Hatoyama, Saitama 350-03, Japan Received 27 July 1992; accepted for publication 24 November 1992 The detailed two-dimensional ordered structures of a monatomic layer of barium (barium oxide) on a W(llO) surface has been investigated by using a molecular beam scattering technique which utilizes a high brightness helium supersonic beam with high coherence. We have successfully obtained, for the first time, diffractive scattering of a helium molecular beam from an ordered structure on the W(llO) surface covered with a sub-monatomic layer of barium (barium oxide).