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[St Druid <tq02ksu@gmail.com>]

Dear all:

The reasonable ixc, iscf, and converged ecut are expected,
moreover, the diemac will be checked carefully.

Maybe it's useful.

Regards.

Dong Bowu.

2009/3/11 文沈 <wshen02@gmail.com>:
> I think I've changed to the hexagonal structure and also changed the
> occopt=3 to show it is metallic,
> Any problems still there?
> My file for the calculation for graphite is as follows,any suggestion or
> correction is welcomed!
>
>   ndtset 6
>
> #First dataset : SC run with kpoints in the IBZ
>    iscf1  3
>   nband1  20
>   nstep1 25
>  kptopt1 1
>  nbdbuf1 0
>  prtden1 1   getden1 0   getwfk1 0    ! Usual file handling data
>
> #Second dataset : NSC run with large number of bands, and points in the IBZ
>     iscf2 -2
>    nband2 20  ! This number of bands might be too low for non-linear optics
> and real part of linear optics
>    nstep2 25
>   kptopt2  1
>   getwfk2  1   getden2 1   ! Usual file handling data
>
> #Third dataset : NSC run with large number of bands, and points in the the
> full BZ
>     iscf3 -2
>    nband3 20  ! This number of bands might be too low for non-linear optics
> and real part of linear optics
>    nstep3 25
>   kptopt3  3
>   getwfk3  2   getden3 1   ! Usual file handling data
>
>
> #Fourth dataset : ddk response function along axis 1
>    iscf4 -3
>   nband4 20   ! This number of bands might be too low for non-linear optics
> and real part of linear optics
>   nstep4  1  nline4  0
>  kptopt4  3
>
>    nqpt4  1  qpt4  0.0d0 0.0d0 0.0d0
>   rfdir4  1 0 0
>  rfelfd4  2
>  getwfk4  3
>
> #Fifth dataset : ddk response function along axis 2
>    iscf5 -3
>   nband5 20   ! This number of bands might be too low for non-linear optics
> and real part of linear optics
>   nstep5  1  nline5  0
>  kptopt5  3
>
>    nqpt5  1  qpt5  0.0d0 0.0d0 0.0d0
>   rfdir5  0 1 0
>  rfelfd5  2
>  getwfk5  3
>
>  Sixth dataset : ddk response function along axis 3
>    iscf6 -3
>   nband6 20   ! This number of bands might be too low for non-linear optics
> and real part of linear optics
>   nstep6  1  nline6  0
>  kptopt6  3
>
>    nqpt6  1  qpt6  0.0d0 0.0d0 0.0d0
>   rfdir6  0 0 1
>  rfelfd6  2
>  getwfk6  3
>
>
> #Data common to all datasets
>  nshiftk 1
>  shiftk  0.0 0.0 0.5
>  ngkpt 9 9 9      ! This is much too low : should be at least 24x24x24
>
>  amu    12
>  diemac 9.0
>  ecut 10.00             ! This is also too low
>  iscf 3
>  ixc 3
>  natom  4 nbdbuf 2
>  ntypat  1
> acell 4.651 4.651 12.67611
> rprim  0.86602540378  -0.5   0.0
>        0.86602540378  0.5   0.0
>        0              0    1
>  xred  0 0 0
>        1/3 1/3 1
>        2/3 2/3 0.5
>        1/3 1/3 0.5
>
>  tnons 72*0.0
>  typat  1 1 1 1  tolwfr  1.e-20
>  znucl  6
>
> occopt=3
>
>
>
> On Tue, Mar 10, 2009 at 9:05 AM, 文沈 <wshen02@gmail.com> wrote:
>>
>> I changed my shiftk as follows
>>  nshiftk 1
>>  shiftk  0.0 0.0 0.5
>> ngkpt 8 8 8
>> I know the number of ngkpt is not enough, but I think at least it should
>> give some graph which have the more or less the same peaks, right?
>> Besides, how can I treat that as metallic system? what should I change
>> except diemac?
>>
>> Thanks a lot,. guys!
>>
>> Wen
>>
>> On Tue, Mar 10, 2009 at 1:55 AM, matthieu verstraete
>> <matthieu.jean.verstraete@gmail.com> wrote:
>>>
>>> your kpoints are completely inappropriate:
>>> 1) you need a much finer mesh for graph*, especially for dielectric
>>> response
>>> 2) the shiftk you use are for an fcc structure, not hexagonal. Please
>>> read the appropriate tutorials (3+4) carefully.
>>> 3) as PMA mentioned, for graphene (an almost metal) and graphite (because
>>> its gap is ridiculously small) you should be treating the system as 
>>> metallic
>>> and including the K point in the samplint (3n x 3n mesh of kpoints). This
>>> last point is less crucial once you converge the mesh properly.
>>>
>>> Matthieu
>>>
>>> On Tue, Mar 10, 2009 at 8:14 AM, Anglade Pierre-Matthieu
>>> <anglade@gmail.com> wrote:
>>>>
>>>> First, I've never done any optic calculation. So I'm not a specialist.
>>>> Now : The dielectric function is the response of your material to an
>>>> electric field. You know that metals and semiconductors have very
>>>> different response to this. Then if one considers only the k-point
>>>> where there is a gap in graphen I would expect a noticeable effect on
>>>> the dielectric function.
>>>>
>>>> regards
>>>>
>>>> PMA
>>>>
>>>> On Mon, Mar 9, 2009 at 11:34 PM, 文沈 <wshen02@gmail.com> wrote:
>>>> > Does this point matter a lot? I am just using the normal sampling as
>>>> > follows
>>>> > nshiftk 4
>>>> >  shiftk  0.5 0.5 0.5
>>>> >          0.5 0.0 0.0
>>>> >          0.0 0.5 0.0
>>>> >          0.0 0.0 0.5
>>>> >  ngkpt 4 4 4
>>>> > could you tell me why the sampling of the k point will have a effect
>>>> > on the
>>>> > calculation result?
>>>> >
>>>> > yours
>>>> > Wen
>>>> >
>>>> > On Mon, Mar 9, 2009 at 12:52 PM, Anglade Pierre-Matthieu
>>>> > <anglade@gmail.com>
>>>> > wrote:
>>>> >>
>>>> >> Does your reciprocal space sampling include the point where
>>>> >> conduction
>>>> >> bands crosses the valence bands ?
>>>> >>
>>>> >> On Mon, Mar 9, 2009 at 6:46 PM, 文沈 <wshen02@gmail.com> wrote:
>>>> >> > Dear Abinit users,
>>>> >> > I am currently using abinit to calculate the dielectric function of
>>>> >> > graphite
>>>> >> > and graphene. But the problem is whatever pseudopotential I use, I
>>>> >> > get
>>>> >> > very
>>>> >> > bad result which I mean I get nearly all 0 for the imaginary part.
>>>> >> > I've
>>>> >> > already made sure that my structures are right.
>>>> >> >
>>>> >> > So anybody who calculate the dielectric function for Carbon please
>>>> >> > give
>>>> >> > me
>>>> >> > some idea what is the problem.
>>>> >> > Thanks a lot !
>>>> >> >
>>>> >> > Yours
>>>> >> > Wen
>>>> >> >
>>>> >>
>>>> >>
>>>> >>
>>>> >> --
>>>> >> Pierre-Matthieu Anglade
>>>> >>
>>>> >
>>>> >
>>>>
>>>>
>>>>
>>>> --
>>>> Pierre-Matthieu Anglade
>>>>
>>>
>>>
>>>
>>> --
>>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>>> Dr. Matthieu Verstraete
>>>
>>> European Theoretical Spectroscopy Facility (ETSF)
>>> Dpto. Fisica de Materiales,
>>> U. del Pais Vasco,
>>> Centro Joxe Mari Korta, Av. de Tolosa, 72,   Phone: +34-943018393
>>> E-20018 Donostia-San Sebastian, Spain        Fax  : +34-943018390
>>>
>>> Mail : matthieu.jean.verstraete@gmail.com
>>> http://www-users.york.ac.uk/~mjv500
>>
>
>



-- 
B.W Dong
State Key Laboratory of Superhard Material
jilin university, Changchun Jilin, China. 130012

tq02ksu@gmail.com [ tq02ksu@email.jlu.edu.cn ]