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Noncanonical localized orbitals and chemisorption
A365 J. FISER Department
of Physical Chemistty,
Charles University,
12840 Prague, Czechoslovakia
Received 15 May 1982 Adsorption of hydrogen atom on the (100) surface of Li, clusters is studied using the diatom&in-molecules method. Special attention is paid to crossing and/or avoided crossing of the ground and excited state potential energy curves for normal approach of H to some surface sites. The most obvious effects of the non-adiabatic behaviour of the system on the course of the adsorption process are considered and the basic aspects of the breakdown of the Bom-Oppenheimer approximation are discussed.
Surface Science 121 (1982) 123-137 North-Holland Publishing Company
123
NONCANONICAL LOCALIZED ORBITALS AND CHEMISORPTION H. Keith MCDOWELL * University of California, LQS Alamos National Laboratoty,
Los Alamos, New Mexico 87545, USA
Received 16 March 1982 A localization scheme is applied to the Hiickel N-atom linear chain in the limit that the chain becomes semi-infinite. It is shown that eigenvalues which arise from the localization procedure serve to separate a set of orbitals localized near the surface from a set of bulk orbitals. The effect of localization on the binding energy of an adatom is also reported where the adatom is assumed to be identical to the bulk atoms. Approximate binding energies are computed by taking combinations of the adatom orbital plus localixed orbitals. Agreement to within 10% with the exact energy is found for the case of localization to two end atoms.
Surface Science 121 (1982) 138-154 North-Holland Publishing Company
138
NEUTRALIZATION IN ION-SURFACE COLLISIONS II. Nonperturbative results C.A. MOYER Department
and Kevin ORVEK
of Physics, Clarkson College of Technology, Potsdam, New York 13676, USA
Received 6 April 1982; accepted for publication 1 June 1982 A theory reported previously for the neutralization probability of slow ions colliding with a solid surface is extended here to treat the large neutralizing rates found in Ion Scattering Spectroscopy. The motion of the ion as well as its lifetime against neutralization contribute to spectral broadening of the ionic levels. In consequence, normally closed neutralization channels may, in fact, be open during collision. The theory is applied to 200 eV helium ions incident on a tungsten surface. Contrary to conventional wisdom, we argue that neutralization in this system is dominated by tunneling processes.
of Physical Chemistty,
Charles University,
12840 Prague, Czechoslovakia
Received 15 May 1982 Adsorption of hydrogen atom on the (100) surface of Li, clusters is studied using the diatom&in-molecules method. Special attention is paid to crossing and/or avoided crossing of the ground and excited state potential energy curves for normal approach of H to some surface sites. The most obvious effects of the non-adiabatic behaviour of the system on the course of the adsorption process are considered and the basic aspects of the breakdown of the Bom-Oppenheimer approximation are discussed.
Surface Science 121 (1982) 123-137 North-Holland Publishing Company
123
NONCANONICAL LOCALIZED ORBITALS AND CHEMISORPTION H. Keith MCDOWELL * University of California, LQS Alamos National Laboratoty,
Los Alamos, New Mexico 87545, USA
Received 16 March 1982 A localization scheme is applied to the Hiickel N-atom linear chain in the limit that the chain becomes semi-infinite. It is shown that eigenvalues which arise from the localization procedure serve to separate a set of orbitals localized near the surface from a set of bulk orbitals. The effect of localization on the binding energy of an adatom is also reported where the adatom is assumed to be identical to the bulk atoms. Approximate binding energies are computed by taking combinations of the adatom orbital plus localixed orbitals. Agreement to within 10% with the exact energy is found for the case of localization to two end atoms.
Surface Science 121 (1982) 138-154 North-Holland Publishing Company
138
NEUTRALIZATION IN ION-SURFACE COLLISIONS II. Nonperturbative results C.A. MOYER Department
and Kevin ORVEK
of Physics, Clarkson College of Technology, Potsdam, New York 13676, USA
Received 6 April 1982; accepted for publication 1 June 1982 A theory reported previously for the neutralization probability of slow ions colliding with a solid surface is extended here to treat the large neutralizing rates found in Ion Scattering Spectroscopy. The motion of the ion as well as its lifetime against neutralization contribute to spectral broadening of the ionic levels. In consequence, normally closed neutralization channels may, in fact, be open during collision. The theory is applied to 200 eV helium ions incident on a tungsten surface. Contrary to conventional wisdom, we argue that neutralization in this system is dominated by tunneling processes.