[Pw_forum] about neb

[Stefano Baroni]

The second step, though instructive, may not be strictly necessary
Also look at the displacement patterns (phonon eigenvectors)
Stefano

On Jun 7, 2004, at 3:33 PM, Wu Rongqin wrote:

> Dear Dr. Baroni,
>
>  
>
> Can you give me some detailed suggestion?
>
> I have some idea but need your opinion:
>
> Firstly , do a calculation on the free SiH4 molecule,
>
> Secondly, do a phonon calculation on a clean surface.
>
> Third, do a phonon calculation on the SiH4+surface,.
>
> Due to the masses difference, the mode frequencies of the surface and 
> SiH4, the mode frequencies of SiH4 may be selected out.
>
>  Do you think it is a way?
>
>  
>
> Regards
>
>  
>
> Rongqin woo
>
>  
>
> -----Original Message-----
> From: pw_forum-admin at pwscf.org [mailto:pw_forum-admin at pwscf.org] On 
> Behalf Of Stefano Baroni
> Sent: 2004年6月7日 21:03
> To: pw_forum at pwscf.org
> Subject: Re: [Pw_forum] about neb
>
>  
>
> The same way as for any other system, I guess (i.e. a free SiH4 
> molecule)
>
>   
>
> For the standpoint of a computer, a "surface" is nothing but a big 
> molecule with periodic boundary conditions.
>
>  As any molecule is treated with periodic boundary conditions in 
> PWscf, you see that there won't be much difference
>
>  (if not for the different weight of the two calculations). Both 
> systems (a free and an adsorbed molecule) require some
>
>  thinking before unleashing supercomputers, though ...
>
>   
>
> Stefano Baroni
>
>   
>
> On Jun 7, 2004, at 2:54 PM, Wu Rongqin wrote:
>
>   
>
> Dear dr. Paolo,
>
>   
>
> Can you tell me how?
>
>   
>
> Thanks
>
>   
>
> Rongqin
>
>   
>
> -----Original Message-----
>
>  From: pw_forum-admin at pwscf.org [mailto:pw_forum-admin at pwscf.org] On 
> Behalf Of Paolo Giannozzi
>
>  Sent: 2004年6月7日 18:32
>
>  To: pw_forum at pwscf.org
>
>  Subject: Re: [Pw_forum] about neb
>
>   
>
> On Monday 07 June 2004 07:09, Wu Rongqin wrote:
>
>   
>
> is it possible to calculate the norm modes of SiH4 absorbed on a 
> surface?
>
>   
>
> of course it is, but it may be difficult to get reliable estimates for 
> typical
>
>  measured quantites, i.e. changes in frequencies and cross sections
>
>  upon adsorption
>
>   
>
> Paolo
>
>  --
>
>  Paolo Giannozzi e-mail: giannozz at nest.sns.it
>
>  Scuola Normale Superiore Phone: +39/050-509876, Fax:-563513
>
>  Piazza dei Cavalieri 7 I-56126 Pisa, Italy
>
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>   
>
> ---
>
>  Stefano Baroni --- SISSA & DEMOCRITOS National Simulation Center
>
>  via Beirut 2-4 34014 Trieste Grignano / ‑[+39] 040 3787 406 (tel) 
> -528 (fax)
>
>   
>
> Please, if possible, don't send me MS Word or PowerPoint attachments
>
>  Why? See: http://www.gnu.org/philosophy/no-word-attachments.html
>
---
Stefano Baroni    ---  SISSA  &  DEMOCRITOS National Simulation Center
via Beirut 2-4 34014 Trieste Grignano / 
[+39] 040 3787 406 (tel) -528 
(fax)

Please, if possible, don't  send me MS Word or PowerPoint attachments
Why? See:  http://www.gnu.org/philosophy/no-word-attachments.html
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