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The properties of K and coadsorbed CO + K on Ru (001) II. Electronic structure
A459 Surface Science 159 (1985) 69-82 North-Holland, Amsterdam
69
INFLUENCE OF THE AMBIENT MEDIUM ON THE DISJOINING PRESSURE OF LIQUID METALLIC FILMS B.V. D E R J A G U I N
a n d V.I. R O L D U G H I N
Institute of Physical Chemistry of the Academy of Sciences of the USSR, 31 Leninski Prospekt, Moscow 117915, USSR Received 1 June 1984; accepted for publication 24 January 1985 We have found the electron density of states in a thin liquid metallic film for an arbitrary form of the boundary conditions for the wavefunctions of the electrons on the film surface. Assuming a Fermi distribution of the electron energies, we have calculated the thermodynamic characteristics of the film and determined the electronic component of the disjoining pressure. It has been shown that the ambient medium and the state of the surface determine the value and the sign of the electronic component of the disjoining pressure. We have determined the conditions for which a stable state of liquid metallic films is ensured.
Surface Science 159 (1985) 83-107 North-Holland, Amsterdam
83
THE PROPERTIES OF K AND COADSORBED II. E l e c t r o n i c s t r u c t u r e J.J. W E I M E R ,
E. U M B A C H
CO + K ON Ru (001)
and D. MENZEL
Fakultiit fur Physik E 20, Technische Universit(zt M~nchen, D-8046 Garching~ Fed. Rep. of Germany Received 29 November 1984; accepted for publication 22 March 1985
The electronic properties of K and CO+ K mixed layers on Ru(001) have been examined in detail with XPS, polarization and angle dependent UPS, and work function changes. The adsorption of K is accompanied by a gradual decrease of the K 2p binding energies and a normal work function behaviour which are discussed in detail. Adsorption of CO on K predosed surfaces also causes a K 2p binding energy decrease at all K coverages which can be understood as repulsion of substrate charge back into the K atom induced by CO orbitals overlapping with the substrate valence band. The complex change in work function caused by CO adsorption is explained by the combination of three effects, CO addition, charge exchange, and K displacement. All results in this and the first paper, in particular the additional peaks in the He I spectra and the HREELS results, are only compatible with the model of a sp2-rehybridized CO molecule in the vicinity of coadsorbed K.
69
INFLUENCE OF THE AMBIENT MEDIUM ON THE DISJOINING PRESSURE OF LIQUID METALLIC FILMS B.V. D E R J A G U I N
a n d V.I. R O L D U G H I N
Institute of Physical Chemistry of the Academy of Sciences of the USSR, 31 Leninski Prospekt, Moscow 117915, USSR Received 1 June 1984; accepted for publication 24 January 1985 We have found the electron density of states in a thin liquid metallic film for an arbitrary form of the boundary conditions for the wavefunctions of the electrons on the film surface. Assuming a Fermi distribution of the electron energies, we have calculated the thermodynamic characteristics of the film and determined the electronic component of the disjoining pressure. It has been shown that the ambient medium and the state of the surface determine the value and the sign of the electronic component of the disjoining pressure. We have determined the conditions for which a stable state of liquid metallic films is ensured.
Surface Science 159 (1985) 83-107 North-Holland, Amsterdam
83
THE PROPERTIES OF K AND COADSORBED II. E l e c t r o n i c s t r u c t u r e J.J. W E I M E R ,
E. U M B A C H
CO + K ON Ru (001)
and D. MENZEL
Fakultiit fur Physik E 20, Technische Universit(zt M~nchen, D-8046 Garching~ Fed. Rep. of Germany Received 29 November 1984; accepted for publication 22 March 1985
The electronic properties of K and CO+ K mixed layers on Ru(001) have been examined in detail with XPS, polarization and angle dependent UPS, and work function changes. The adsorption of K is accompanied by a gradual decrease of the K 2p binding energies and a normal work function behaviour which are discussed in detail. Adsorption of CO on K predosed surfaces also causes a K 2p binding energy decrease at all K coverages which can be understood as repulsion of substrate charge back into the K atom induced by CO orbitals overlapping with the substrate valence band. The complex change in work function caused by CO adsorption is explained by the combination of three effects, CO addition, charge exchange, and K displacement. All results in this and the first paper, in particular the additional peaks in the He I spectra and the HREELS results, are only compatible with the model of a sp2-rehybridized CO molecule in the vicinity of coadsorbed K.