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Final energy distributions of the electronic system in atom or ion scattering from metal surfaces
A327 Surface Science 216 (1989) 249-262 North-Holland, Amsterdam
249
FINAL ENERGY DISTRUWTIONS IN ATOM OR ION SCATTERING Hiroshi NAKANISHI, Department
OF THE ELECTRONIC SYSTEM FROM METAL SURFACES
Hideaki KASAI and Ayao OKIJI
of Applied Physics, Osaka University,
Suita, Osaka 565, Japan
Received 15 November 1988; accepted for publication
14 February 1989
The electronic energy transfer associated with the charge transfer in the scattering of particles from metal surfaces is investigated within the framework of the non-interacting time-dependent Newns-Anderson model in the wide-band limit. In this paper, the final energy distributions of the electronic system are shown to be decomposed into parts related to the initial as well as the final charge state of the particles (neutral atoms and positive ions). As a result of numerical calculations, several characteristic structures are found in the final energy distributions. Their origins are explained briefly.
263
Surface Science 216 (1989) 263-269 North-Holland, Amsterdam
EXTRACTION OF Ir-Ir ADATOM INTERACTION ON Ir(100) FROM FIELD ION MICROSCOPY OF IRIDIUM CLUSTER STRUCTURES P.R. SCHWOEBEL
STRENGTHS
and Peter J. FEIBELMAN
Sandia National Laboratories,
Albuquerque,
NM 87185, USA
Received 1 September 1988; accepted for publication
30 December 1988
The interaction energetics of iridium atoms self-adsorbed on Ir(lOO) are inferred from field ion microscopy observations which show that for 5 or fewer adatoms the most stable cluster configuration is a linear chain oriented in a (110) surface direction, while for 6 or more adatoms certain two-dimensional islands are the most stable. The critical number of adatoms beyond which island growth is preferred, together with the observed stable island configurations for 6 and 7 atoms, imply relatively tight bounds on possible lattice gas interaction parameters once reasonable assumptions are made regarding their falloff with adatom separation. The third near-neighbor interaction must be attractive and non-negligible, indicating that relatively long-range interactions between the Ir adatoms are present. In addition, configurations involving second near-neighbor interactions must be repulsive if the observed cluster configurations are to be explained.
249
FINAL ENERGY DISTRUWTIONS IN ATOM OR ION SCATTERING Hiroshi NAKANISHI, Department
OF THE ELECTRONIC SYSTEM FROM METAL SURFACES
Hideaki KASAI and Ayao OKIJI
of Applied Physics, Osaka University,
Suita, Osaka 565, Japan
Received 15 November 1988; accepted for publication
14 February 1989
The electronic energy transfer associated with the charge transfer in the scattering of particles from metal surfaces is investigated within the framework of the non-interacting time-dependent Newns-Anderson model in the wide-band limit. In this paper, the final energy distributions of the electronic system are shown to be decomposed into parts related to the initial as well as the final charge state of the particles (neutral atoms and positive ions). As a result of numerical calculations, several characteristic structures are found in the final energy distributions. Their origins are explained briefly.
263
Surface Science 216 (1989) 263-269 North-Holland, Amsterdam
EXTRACTION OF Ir-Ir ADATOM INTERACTION ON Ir(100) FROM FIELD ION MICROSCOPY OF IRIDIUM CLUSTER STRUCTURES P.R. SCHWOEBEL
STRENGTHS
and Peter J. FEIBELMAN
Sandia National Laboratories,
Albuquerque,
NM 87185, USA
Received 1 September 1988; accepted for publication
30 December 1988
The interaction energetics of iridium atoms self-adsorbed on Ir(lOO) are inferred from field ion microscopy observations which show that for 5 or fewer adatoms the most stable cluster configuration is a linear chain oriented in a (110) surface direction, while for 6 or more adatoms certain two-dimensional islands are the most stable. The critical number of adatoms beyond which island growth is preferred, together with the observed stable island configurations for 6 and 7 atoms, imply relatively tight bounds on possible lattice gas interaction parameters once reasonable assumptions are made regarding their falloff with adatom separation. The third near-neighbor interaction must be attractive and non-negligible, indicating that relatively long-range interactions between the Ir adatoms are present. In addition, configurations involving second near-neighbor interactions must be repulsive if the observed cluster configurations are to be explained.