[Wien] Surface dipole of a metal

[sjalali at sci.ui.ac.ir]

Dear Prof. Laurence Marks,
Hi,
Thank you for your inquiry. Calculating the surface dipole of a metal  
can be an interesting and challenging task. While I cannot provide a  
personal account of testing the DIPOLE option in AIM, I can suggest an  
approach that might be helpful.

The surface dipole moment, denoted as $\mu$ in Debye, can be  
calculated using the Helmholtz equation:

$\Delta\Phi = \frac{1}{2\pi\Theta}\frac{\mu}{A}$,

where $\Delta\Phi$ is the work-function change in eV, $A$ is the area  
per ($1\times1$) surface unit cell in $\text{\AA}^2$, $\Theta$  
represents the adsorbate coverage in monolayers. The equation  
expressing the surface dipole moment is given by Eq. (4) of  Ref.  
[Physical Review B, 73, 165424 (2006)], see also Fig. 2 of this  
reference, where $\mu$ and $\Delta \Phi$ are shown as a function of  
coverage for O in the fcc-hollow site.

The work function, as the difference between the electrostatic  
potential in the middle of the vacuum and the Fermi energy of the  
slab, can be calculated using Eq. (1) of  Ref.  
[http://dx.doi.org/10.1016/j.commatsci.2009.09.027], you would also  
see Fig. 2 of [http://dx.doi.org/10.1063/1.3486216].

I hope this suggestion is helpful to you. Should you have any further  
questions or require more specific guidance, please feel free to ask.
Good luck with your research!
Warmest Regards,
Saeid


 



Quoting Laurence Marks <laurence.marks at gmail.com>:

> I wonder if anyone has a good suggestion for calculating the surface  
> dipole of a metal (e.g. Al). The DIPOLE option in aim might do it,  
> although I have no idea if that works. If anyone has tested it  
> please let me know; alternatively, if you have an inspiration on how  
> to test it against a calibrant that would be informative.
>     
>    I am always hopeful...
>     
> --
>        Professor Laurence Marks (Laurie)
> Department of Materials Science and Engineering
> Northwestern University
> www.numis.northwestern.edu[1]
> "Research is to see what everybody else has seen, and to think what  
> nobody else has thought", Albert Szent-Györgyi



Links:
------
[1] http://www.numis.northwestern.edu
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