[Pw_forum] about neb

[Wu Rongqin]

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) 
 
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