The effect of hydrogen on single-atom surface diffusion
- Sandia National Labs., Albuquerque, NM (United States)
Field ion microscope observations show that chemisorbed hydrogen has a pronounced effect on the mobility of individual atoms on metal surfaces. The effect is found to be qualitatively different depending on the displacement mechanism. On Rh(100) and Rh(311), where self-diffusion proceeds by site-to-site hopping, the rate if migration is significantly increased by exposure of the surface to hydrogen. Surprisingly, the enhancement is found to depend on the hydrogen coverage. In contrast, on Pt(100), where the displacement mechanism is atomic exchange, self-diffusion is inhibited by chemisorbed hydrogen. Here, exchange displacements are suppressed to the point where hopping displacements become energetically accessible. These results show how chemical adsorbates can be used to influence both the diffusion rate and the transport mechanism of atoms on surfaces and provide valuable insight into our understanding of surfactant-mediated thin-film growth processes.
- Research Organization:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 559962
- Report Number(s):
- CONF-970443-; TRN: 97:005895-0074
- Resource Relation:
- Conference: 213. national meeting of the American Chemical Society, San Francisco, CA (United States), 13-17 Apr 1997; Other Information: PBD: 1997; Related Information: Is Part Of 213th ACS national meeting; PB: 2904 p.
- Country of Publication:
- United States
- Language:
- English
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