[Pw_forum] Strained Graphene Nanoribbon

[Arles V. Gil Rebaza]

I agree with Ricardo, you need a convergence of total energy (or the
property you want to analyze)... this comment I told you by email some day
ago....!!!

 PhD std. Arles V. Gil Rebaza
 Instituto de Física de La Plata
 La Plata - Argentina


2011/5/12 Ricardo Faccio <rfaccio at fq.edu.uy>

> Hi
> The number of k points is always chosen in terms of convergence of some
> physical property, this is the final decision. Dependent of the metallic
> nature of your case, you may choose high or lower number of k-points.
> In the case of codes with not so efficient methods for Brillouin Zone
> integration, e.g. SIESTA, you need to use a considerable amount of
> k-points in order to reach convergence.
> But in QE, you can get the best choice, going step by step, increase
> little by little, the number of k-pints, until reaching convergence.
> Certainly, you will get a number considerably lower than 100.
> Additionally, H-saturated zigzag nanoribbons are insulators -
> antiferromagnets, so maybe you will need few kpoints.
> Regards
> Ricardo
>
> > Hi Arles,
> >
> > Sorry, I realized the same, the reason I chose 1 1 100 was, I was using
> > another quantum software and the forum there had displayed results with
> > having the k points as 100, so to be in better position to be able to
> > compare with their result I chose 100, but as you have pointed out and I
> > learned myself, the decision was indeed insane. I am still trying to
> learn
> > how specifically can one decide on k points, do you have any suggestion
> on
> > k
> > points for my input file,
> >
> > On Thu, May 12, 2011 at 10:11 AM, Arles V. Gil Rebaza
> > <arvifis at gmail.com>wrote:
> >
> >> Why do you choose  1 1 100  k-points.... this is an insane
> >> desicion....!!!!!!
> >>
> >> PhD std. Arles V. Gil Rebaza
> >> Instituto de Física de La Plata
> >> La Plata - Argentina
> >>
> >>
> >>
> >>
> >>
> >> 2011/5/12 swapnil chandratre <swapnil.chandratre at gmail.com>
> >>
> >>> Hi,
> >>>
> >>> Thank you for sparing time on this, I will try to get it resolved
> >>> sooner.
> >>> Any suggestions are heartily welcomed.
> >>>
> >>>
> >>> On Thu, May 12, 2011 at 9:03 AM, Paolo Giannozzi
> >>> <giannozz at democritos.it>wrote:
> >>>
> >>>>
> >>>> On May 12, 2011, at 15:49 , swapnil chandratre wrote:
> >>>>
> >>>> >  I just wanted to know if there is no error with the script
> >>>>
> >>>> I don't know if there is an error in the script. I just tried to
> >>>> run it on a PC, it starts but it is definitely too large for a
> >>>> single CPU. Since the code writes > 800Mb Kohn-Sham
> >>>> wavefunctions for each of the 100 k-points, insufficient disk
> >>>> space looks like a promising explanation
> >>>>
> >>>> P.
> >>>> ---
> >>>> Paolo Giannozzi, Dept of Chemistry&Physics&Environment,
> >>>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> >>>> Phone +39-0432-558216, fax +39-0432-558222
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> _______________________________________________
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> >>>>
> >>>
> >>>
> >>>
> >>> --
> >>> Regards,
> >>> Swapnil Chandratre
> >>> Graduate Student
> >>> Dept. of Mechanical Engineering,
> >>> University of Houston,
> >>> Houston, TX
> >>> (M)-713-294-9546
> >>>
> >>> _______________________________________________
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> >>>
> >>>
> >>
> >>
> >> --
> >> ###--------->   Arles V.   <---------###
> >>
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> >>
> >
> >
> > --
> > Regards,
> > Swapnil Chandratre
> > Graduate Student
> > Dept. of Mechanical Engineering,
> > University of Houston,
> > Houston, TX
> > (M)-713-294-9546
> > _______________________________________________
> > Pw_forum mailing list
> > Pw_forum at pwscf.org
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> >
>
>
> --
> -------------------------------------------------
>  Dr. Ricardo Faccio
>  Prof. Adjunto de Física
>  Mail: Cryssmat-Lab., Cátedra de Física, DETEMA
>  Facultad de Química, Universidad de la República
>       Av. Gral. Flores 2124, C.C. 1157
>       C.P. 11800, Montevideo, Uruguay.
>  E-mail: rfaccio at fq.edu.uy
>  Phone: 598 2 924 98 59
>         598 2 929 06 48
>  Fax:   598 2 9241906
>  Web:  http://cryssmat.fq.edu.uy/ricardo/ricardo.htm
>
>
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-- 
###--------->   Arles V.   <---------###
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