[Pw_forum] DCC correction to electrostatic potential

[lan haiping]

Dear Emine
Thank you for this detailed description.

Regards,
Hai-Ping

On Thu, Feb 19, 2009 at 11:39 PM, e kb <eminekb at yahoo.com> wrote:

> Dear Hai-Ping
> Nick is right, DCC for partial periodicity is not in the cvs version of the
> code yet.
> The main issue is not the "whichbc" parameter that you've checked in the
> Multigrid directory. The way that the true potential is
> calculated (add_boundary.f90) and Poisson equation that is solved should be
> modified accordingly (add_dcc_field.f90).
> Regards,
>
> Emine Kucukbenli,
> grad student, SISSA, Italy.
>
> --- On *Thu, 2/19/09, lan haiping <lanhaiping at gmail.com>* wrote:
>
> From: lan haiping <lanhaiping at gmail.com>
> Subject: Re: [Pw_forum] DCC correction to electrostatic potential
> To: "PWSCF Forum" <pw_forum at pwscf.org>
> Date: Thursday, February 19, 2009, 4:12 AM
>
>
> Dear Nick,
> Thanks.
> Therefore, My problem is just due to wrong BC handling by QE. I found the
> settings for boundary conditions at $QE/Multigrid, and just thought it
> should be OK for all possible aperiodic situations.
> Would you mind to tell me
> which subroutine in $QE/EE accounts for boundary settings ?
>
> Regards,
> Hai-Ping
>
> On Thu, Feb 19, 2009 at 1:20 AM, Nicholas E. Singh-Miller <nedward at mit.edu
> > wrote:
>
>> Dear Hai-Ping,
>>
>> I am looking at espresso-4.1CVS.
>>
>> Looking at the subroutines in EE/, it looks like the DCC correction is
>> currently only coded for isolated systems -- in which case the
>> calculataion of BCs for a CNT would cut through the charge density. (but I
>> could be missing something).
>>
>> Regads,
>>
>> Nick
>>
>> On Wed, 18 Feb 2009, lan haiping wrote:
>>
>> > Dear All,
>> >
>> >  I did test calculations on DCC correction implemented in CVS version.
>> > I came to  problems when i examine the results of electrostatic
>> potential.
>> > Would you please give me some hints ?
>> > My test calculation is a CNT (10,10)  system,  and the setting for
>> > DCC correction is
>> >        which_compensation ='dcc',
>> >        ecutcoarse = 100.0,
>> >        n_charge_compensation= 5,
>> >        nlev = 4,
>> >        whichbc(1)= 0, whichbc(2)=0,
>> >        whichbc(3)=1,
>> > But the final fermi energy i obtained is -3.99 eV, which is not
>> consistent
>> > with
>> > previous report on workfunction of CNTs(about 4.6 eV ).
>> >
>> > Best,
>> > Hai-Ping
>> >
>> >
>> >
>>
>> *****************************************
>> Nicholas E. Singh-Miller
>> Ph.D. Candidate
>> Prof. Marzari Group (quasiamore.mit.edu)
>> Materials Science and Engineering
>> Massachusetts Institute of Technology
>> 13-4066
>> (617)324-0372
>> *****************************************
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>
>
>
> --
> Hai-Ping Lan
> Department of Electronics ,
> Peking University , Bejing, 100871
> lanhaiping at gmail.com, hplan at pku.edu.cn
>
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-- 
Hai-Ping Lan
Department of Electronics ,
Peking University , Bejing, 100871
lanhaiping at gmail.com, hplan at pku.edu.cn
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