[Pw_forum] fluctuation in SCF energies of CO adsorbed on Pd110

[Axel Kohlmeyer]

On Mon, Apr 21, 2014 at 12:03 AM, David Foster <davidfoster751 at yahoo.com> wrote:
> Dear Yun
> Thanks for your rapid answer. Considering your answer, I have two more questions:
>
> 1- In the system I have carbon monoxide. carbon atom has 4 electron in its valance. between O and C there is a triple bond. So, carbon may have one unpaired electron that needs spin-polarization defined. Is it right?

wrong. electrons cannot be "assigned" to individual atoms, they occupy
"molecular" orbitals. please help yourself to a little quantum
chemistry refresher.

> 2- Surface of metals due to the charge density near to the surface needs spin-polarization. Is it right?

wrong. you need spin polarization only if you have unpaired electrons..

> One more point. I have prepared input with one graphical program. When I see the input file with XCrysDen, in the primitive form everything is OK, but in conventional form, three to four Pd atoms in the edge of cell seems to be missing!!!!

that is just visualization. probably your initial geometry has some
rounding errors in the positions.

axel.

> Regards
>
> David Foster
>
> Ph.D. Student of Chemistry
>
> --------------------------------------------
> On Sun, 4/20/14, Yun Wang <yun.wang at griffith.edu.au> wrote:
>
>  Subject: Re: [Pw_forum] fluctuation in SCF energies of CO adsorbed on Pd110
>  To: "PWSCF Forum" <pw_forum at pwscf.org>
>  Date: Sunday, April 20, 2014, 2:41 PM
>
>  Hi David,I think
>  you need not consider the spin polarization for this system,
>  which will accelerate the
>  convergancy.Cheers,Yun
>
>
>
>
>
>  On Mon, Apr 21, 2014
>  at 2:20 AM, David Foster <davidfoster751 at yahoo.com>
>  wrote:
>
>
>  Dear users
>
>
>
>  I have prepared an input for interaction between CO and
>  Pd(110). I optimized 3*3*3 supercell of Pd bulk, and then
>  cleaved a 110 surface and constructed a slab. I inserted CO
>  molecule which has been optimized with QE5.0.2 in it. Now, I
>  try to optimize this mixed system (CO+Pd(110)).
>
>
>
>
>
>  My main problem is that in scf I see the fluctuation in
>  energies. My input and output has been attached. In all
>  calculations I used QE5.0.2 and the same USPP. I used PBE
>  DFT in the PP. I used nspin=2 due to the presence of oxygen
>  atom. I introduced start_magnetization for all species. I
>  fixed three bottom layers in the cell. I used ibrav=14 to
>  optimize bulk phase of Pd, and didn't change it in all
>  computation.
>
>
>
>  I used degauss=0.001RY. In addition I used smearing
>  technique for both bulk and slab.
>
>
>
>  The run is continuing, but I think finally, I will encounter
>  with problem.
>
>
>
>  Any idea for rapid convergence and solve the issue in
>  fluctuation energy is appreciated.
>
>
>
>
>
>
>
>
>
>  Regards
>
>
>
>  David Foster
>
>
>
>  Ph.D. Student of Chemistry
>  _______________________________________________
>
>  Pw_forum mailing list
>
>  Pw_forum at pwscf.org
>
>  http://pwscf.org/mailman/listinfo/pw_forum
>
>
>
>  --
>
>  Dr. Yun Wang
>  Research Fellow
>  Centre for Clean Environment and Energy
>  Griffith School of Environment
>  Gold Coast Campus, Griffith University
>  QLD 4222, Australia
>  Tel:(61-7) 5552 8456
>  Fax:(61-7) 5552 8067
>
>
>
>
>  -----Inline Attachment Follows-----
>
>  _______________________________________________
>  Pw_forum mailing list
>  Pw_forum at pwscf.org
>  http://pwscf.org/mailman/listinfo/pw_forum
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://pwscf.org/mailman/listinfo/pw_forum



-- 
Dr. Axel Kohlmeyer  akohlmey at gmail.com  http://goo.gl/1wk0
College of Science & Technology, Temple University, Philadelphia PA, USA
International Centre for Theoretical Physics, Trieste. Italy.