2020-04-07T23:07:27Z
http://digital.csic.es/dspace-oai/request
oai:digital.csic.es:10261/21807
2016-02-16T06:14:16Z
com_10261_14181
com_10261_4
col_10261_14182
2010-03-02T10:44:05Z
urn:hdl:10261/21807
Kramers' turnover theory for diffusion of Na atoms on a Cu(001) surface measured by He scattering
Guantes, R.
Vega, J. L.
Miret-Artés, Salvador
Pollak, Eli
12 pages, 7 figures.
The diffusion of adatoms and molecules on a surface at low coverage can be measured by helium scattering. The experimental observable is the dynamic structure factor. In this article, we show how Kramers' turnover theory can be used to infer physical properties of the diffusing particle from the experiment. Previously, Chudley and Elliot showed, under reasonable assumptions, that the dynamic structure factor is determined by the hopping distribution of the adsorbed particle. Kramers' theory determines the hopping distribution in terms of two parameters only. These are an effective frequency and the energy loss of the particle to the bath as it traverses from one barrier to the next. Kramers' theory, including finite barrier corrections, is tested successfully against numerical Langevin equation simulations, using both separable and nonseparable interaction potentials. Kramers' approach, which really is a steepest descent estimate for the rate, based on the Langevin equation, involves closed analytical expressions and so is relatively easy to implement. Diffusion of Na atoms on a Cu(001) surface has been chosen as an example to illustrate the application of Kramers' theory.
2010-03-02T10:44:05Z
2010-03-02T10:44:05Z
2003-08-01
artículo
Journal of Chemical Physics 119(5): 2780 (2003)
0021-9606
http://hdl.handle.net/10261/21807
10.1063/1.1587687
eng
http://dx.doi.org/10.1063/1.1587687
openAccess
American Institute of Physics