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Friction and sticking coefficients of rare gases approaching a metal surface
A48 Surface Science 137 (1984) 167-180 North-Holland, Amsterdam
167
FRICTION AND STICKING COEFFICIENTS APPROACHING A METAL SURFACE F. SOLS, F. FLORES Dhisi6n
and N. GARCIA
de Fisica, Unioersidad Aut&wma,
Received
OF RARE GASES
8 June 1983; accepted
Cantoblanco, Madud
for publication
14 October
34, Spain
1983
By means of a perturbative approach, we have obtained analytic expressions for the friction and sticking coefficients of rare gases approaching a metal surface. We have applied our calculations to He. and found results that are in agreement with other independent calculations. showing that the electron-hole pairs cannot play an important role in the sticking processes in scattering of He on metal surfaces.
Surface Science 137 (1984) 181-196 North-Holland, Amsterdam
I81
A MOLECULAR ORBITAL STUDY OF HYDROGEN ATOMS IMPLANTED IN TITANIUM METAL CLUSTERS Frank LIU Deparrment
of Chemrstr)t. Huarhong Normal
Unroersity, Wuhan, People2 Rep. of Chrna
and A.L. COMPANION Departmenf Received
of Chemislry,
Universrty of Kentucky,
18 July 1983; accepted
for publication
Lextngton,
Kentucky
16 September
40506 -0055, USA
1983
Extended Hiickel Molecular Orbital (EHMO) theory has been applied to the problem of hydrogen atom site location in titanium clusters Ti,. Ti,, Ti,, and Ti,,, the latter simulating the hcp metal face (0001). In agreement with previous ab initio calculations. it is found that an external position for the hydrogen atom over a three-fold coordination site is favored over all internal positions in a perfect crystal. Among the internal positions, tetrahedral sites are favored over octahedral ones. The binding energies of internal sites appear to be enhanced by the presence of vacancies; indeed, the only internal site that is stable with respect to the surface is a tetrahedral hole adjacent to a vacancy. Density of states diagrams for Ti,, show a hydrogen induced band at approximately 6.5 eV below the Fermi level, in agreement with photoemission results.
167
FRICTION AND STICKING COEFFICIENTS APPROACHING A METAL SURFACE F. SOLS, F. FLORES Dhisi6n
and N. GARCIA
de Fisica, Unioersidad Aut&wma,
Received
OF RARE GASES
8 June 1983; accepted
Cantoblanco, Madud
for publication
14 October
34, Spain
1983
By means of a perturbative approach, we have obtained analytic expressions for the friction and sticking coefficients of rare gases approaching a metal surface. We have applied our calculations to He. and found results that are in agreement with other independent calculations. showing that the electron-hole pairs cannot play an important role in the sticking processes in scattering of He on metal surfaces.
Surface Science 137 (1984) 181-196 North-Holland, Amsterdam
I81
A MOLECULAR ORBITAL STUDY OF HYDROGEN ATOMS IMPLANTED IN TITANIUM METAL CLUSTERS Frank LIU Deparrment
of Chemrstr)t. Huarhong Normal
Unroersity, Wuhan, People2 Rep. of Chrna
and A.L. COMPANION Departmenf Received
of Chemislry,
Universrty of Kentucky,
18 July 1983; accepted
for publication
Lextngton,
Kentucky
16 September
40506 -0055, USA
1983
Extended Hiickel Molecular Orbital (EHMO) theory has been applied to the problem of hydrogen atom site location in titanium clusters Ti,. Ti,, Ti,, and Ti,,, the latter simulating the hcp metal face (0001). In agreement with previous ab initio calculations. it is found that an external position for the hydrogen atom over a three-fold coordination site is favored over all internal positions in a perfect crystal. Among the internal positions, tetrahedral sites are favored over octahedral ones. The binding energies of internal sites appear to be enhanced by the presence of vacancies; indeed, the only internal site that is stable with respect to the surface is a tetrahedral hole adjacent to a vacancy. Density of states diagrams for Ti,, show a hydrogen induced band at approximately 6.5 eV below the Fermi level, in agreement with photoemission results.