Growth and hydrogenation of ultra-thin Mg films on Mo(111)

Christopher Worsøe Ostenfeld, Jonathan Conrad Davies, Tejs Vegge, Ib Chorkendorff

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Abstract

The growth and hydrogenation of ultra-thin magnesium overlayers have been investigated on a Mo(1 1 1) single crystal substrate. For increasing magnesium coverages we observe intermediate stages in the TPD and LEISS profiles, which illustrate the transition from one monolayer to multilayer growth. Hydrogen cannot be adsorbed on magnesium films under UHV conditions. However, when evaporating Mg in a hydrogen background, a hydrogen overlayer is seen to adsorb at the Mg surface, due to the catalytic interaction with the Mo(1 1 1) substrate and subsequent spill-over. We show that two monolayers of Mg are necessary to sustain this purely adsorbed state. Using predissociated hydrogen we show that the hydride formation is self-stabilizing and the hydride only decomposes at a temperature where a considerable desorption of magnesium occurs.
Original languageEnglish
JournalSurface Science
Volume584
Issue number1
Pages (from-to)17-26
ISSN0039-6028
DOIs
Publication statusPublished - 2005

Keywords

  • Magnesium
  • Metallic films
  • Thermal desorption spectroscopy
  • Density functional theory
  • Hydrogen molecule

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