| Autor: |
A. Iwamoto, M. Takizawa, Tomoki Akita, Yoshihito Maeda, Y. Kitsudo, Halina Matsumoto, Tomoaki Nishimura, Yoshiaki Kido, Kei Mitsuhara |
| Rok vydání: |
2009 |
| Předmět: |
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| Zdroj: |
Surface Science. 603:2108-2114 |
| ISSN: |
0039-6028 |
| DOI: |
10.1016/j.susc.2009.04.008 |
| Popis: |
The effect of a positive charge left to a small metal particle immediately after photoemission, so called the final state effect is studied for Au 4f binding energy ( E B ) shifts. The size and shape of Au nano-particles were determined by high-resolution medium energy ion scattering combined with scanning electron microscopy of a field emission type. The shape of Au nano-particles is well approximated by a partial sphere with diameter d and height h . It is found that the E B shift is well expressed as number of atoms per particle ( n A ) and independent of support species. The E B shift changes dramatically at a critical n A value of ∼70 atoms, where metal–nonmetal transition takes place. In the nonmetal region, the E B shift increases steeply almost exponentially with decreasing n A and in contrast, gradually decreases with increasing n A in the metallic region. The effect of the positive charge of an Au 4f vacancy created by photoemission is expressed by the relaxation time τ and the effective charge + α e when the photoelectron just leaves the Au particle surface ( e : electron charge, α |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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