[Pw_forum] a not reasonable initial path for NEB calculation

lfhuang lfhuang at theory.issp.ac.cn
Mon Mar 30 01:53:46 CEST 2009

Dear Paolo Giannozzi and Prasenjit Ghosh:
    Thank you for your kind attention! 
    I view the initial path in xcrysden, which should mean this is not related to the QE version (am I right?), And 
there are some C atoms even displace over several lattice constants or substituted by the H adatom. From other
literatures, the H atom should diffuse along the C-C bond, based on which I added 3-7 intermediate images, but 
that doesn't make any different!
    Although in the first and last images, as P. Giannozzi mentioned, the C atoms are somewhat distorted by the 
H adatom, the displacement of them are small (less than 0.5 angstroms, the lattice constant is 2.5). 
    So I want to ask, when you meet this kind of failure of the interpolation for the initial path, what would you 
do to get an reasonable one? Thanks!

Best Wishes!

Yours Sincerely
L. F. Huang
> Date: Sun, 29 Mar 2009 19:54:17 +0200
> From: Paolo Giannozzi 
> Subject: Re: [Pw_forum] a not reasonable initial path for NEB
> 	calculation
> To: PWSCF Forum 
> Message-ID: 
> Content-Type: text/plain; charset="us-ascii"
> On Mar 29, 2009, at 16:14 , lfhuang wrote:
> > I am calculating the diffusion barrier of atomic H on graphene  
> > layer using NEB method. The first_image and last_image correspond  
> > to structures with a H atom on top of two nearest C atoms,  
> > respectively. However, the interpolated initial path is not  
> > reasonable that there are some largely displaced C atoms in the  
> > configurations between first and last images, because [...]
> >
> ...the C atom in the first and the last image were not ordered in the  
> same way.
> >      In addition, I use the QE-3.2.3 version
> >
> no longer supported, use it at your own risk.
> >     Could anyone help me? I'd like to appreciate any good advice!
> >
> I think xcrysden should be able to visualize the path
> P.
> ---
> Paolo Giannozzi, Democritos and University of Udine, Italy
> Message: 7
> Date: Sun, 29 Mar 2009 20:49:09 +0200
> From: Prasenjit Ghosh 
> Subject: Re: [Pw_forum] a not reasonable initial path for NEB
> 	calculation
> To: PWSCF Forum 
> Message-ID:
> Content-Type: text/plain; charset="gb2312"
> if u have some approximate idea of the path, u can provide the guess path by
> mentioning the images using the option "intermediate image" in the card
> Prasenjit.

L.F.Huang(黄良锋) lfhuang at theory.issp.ac.cn
Add: Research Laboratory for Computational Materials Sciences,
Instutue of Solid State Physics,the Chinese Academy of Sciences,
P.O.Box 1129, Hefei 230031, P.R.China
Tel: 86-551-5591464-328(office)
Fax: 86-551-5591434
Web: http://theory.issp.ac.cn (website of our theory group)
http://www.issp.ac.cn    (website of our institute)

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