[Pw_forum] INPUT file for average.x

[Nicholas E. Singh-Miller]

Hi,

Alice Runi's thesis from 1997 talks about macroscopic averages at 
interfaces, in chapter 5.

http://www.sissa.it/cm/thesis/1997/ruini.ps.gz

maybe a good starting point.

-Nick

On Mon, 26 Apr 2010, Stefano Baroni wrote:

> 
> On Apr 26, 2010, at 8:41 AM, Gabriele Sclauzero wrote:
> 
> 
>
>       wulilixiangguo at sina.com wrote:
>             I read below and have a question about
>             macroscopic averages. If my
>
>             system have a surface between two materials which
>             have different lattice
>
>             constant.
> 
>
>       Do you mean an interface? (I would say a "surface" only if
>       one of the two "materials" is
>       vacuum, but maybe I'm pedantic...)
>
>       How to set the awin?
>
>       Not sure of this, but I think that it is not a good idea to
>       use macroscopic averages when
>       there is a change in the periodicity. For instance, in a
>       recent paper by Singh-Miller and
>       Marzari (PRB, 2010) it has been reported that the technique
>       is not well suited for slab
>       geometries when you account for the relaxation of the
>       distances between layers.
> 
>
>       How to macroscopic it twice?
>
>       Maybe I don't understand this point.
>
>       You could run the program twice, with two different window
>       sizes, in order to match the
>       two different lattice spacings, but then I don't know if
>       there is a way to give a
>       meaningful interpretation to the data at the interface.
> 
> 
> What you propose, Gabriele, is perfectly legitimate and has been done
> indeed af few times in the good ol' times when macroscopic averages had
> been invented. I do not remember by heart the reference, but somebody may
> want to try a bibliographic search with "resta" and "baroni" as authors
> and select the title(s) that may suggest the investigation of lattice
> mismatched interfaces.
> 
> SB
> 
> ---
> Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -
> Trieste
> http://stefano.baroni.me [+39] 040 3787 406 (tel) -528 (fax) /
> stefanobaroni (skype)
> 
> La morale est une logique de l'action comme la logique est une morale de
> la pensée - Jean Piaget
> 
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> Why? See:  http://www.gnu.org/philosophy/no-word-attachments.html
> 
> 
> 
> 
> 
> 
> 
> 
>

*****************************************
Nicholas E. Singh-Miller
Prof. Marzari Group (quasiamore.mit.edu)
Materials Science and Engineering
Massachusetts Institute of Technology
13-4066
(617)324-0372
*****************************************