Dear Huang, You are the best person to guess the best initial path. What I would suggest is to get an idea as to how the H atom diffuses (either by searching literature or from some chemical insight) and provide the guess path by specifying the intermediate images with the option "intermediate_image". This way the code uses your guess path rather than doing an interpolation.
Prasenjit. 2009/3/30 lfhuang <lfhuang at theory.issp.ac.cn> > 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 > > ATOMIC_POSITIONS > > > > Prasenjit. > > > > ------ > ====================================================================== > L.F.Huang(???) 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://theory.issp.ac.cn>http://www.issp.ac.cn> (website of our > institute) > ====================================================================== > <http://www.issp.ac.cn> > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum > > -- PRASENJIT GHOSH, POST-DOC, ROOM NO: 265, MAIN BUILDING, CM SECTION, ICTP, STRADA COSTERIA 11, TRIESTE, 34104, ITALY PHONE: +39 040 2240 369 (O) +39 3807528672 (M) -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090330/e6c72ae8/attachment.htm
