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[Tonatiuh Rangel Gordillo <tonatiuh@cio.mx>]

Dear Anglade,
I made a test with a higher ecut, but, the spectra does not changes too much.
According to the optical response, the material starts to absorb at an
energy close to 4 eV but the band gap calculated in the same routine is
around 2 eV.

I think I have something wrong in the input file.
If someone finds something wrong please let me know.

Tonatiuh.

The input file is attached.



> Dear Anglade,
>         I also found this kind warning in my ddk calculation. Since I have
> done the test of convergence on the ecut and k-mesh, I am afraid
> that it might not raised by the small ecut. I'd like to compared
> the calculated results with the experimental values to find this
> warning is fatal or not. By the way, I do the RF calculation of
> the phonons at the zone-center using v4.6.5 and the input file is
> attached.
>
>
> Anglade Pierre-Matthieu <anglade@gmail.com> дµÀ£º
>   Hi,
>
> Though I'm not quite familiar with optics calculation it seems very
> plausible that the abscnece of ecut convergency is at the root of your
> problems. Have you try to use a much larger ecut ?
>
> regards
>
> PMA
>
>   On 11/29/06, Tonatiuh Rangel Gordillo <tonatiuh@cio.mx> wrote:  Dear
> abinit users.
>
> I am making an optics calculation with abinit-4.6.5
>
> I want to obtain the linear response for a molecule in a big box, and I
> follow the steps that are given on the tutorial, however, the response
> function it gives me does not seem to be right. It shows a vacuum size
> that does not correspond to the vacuum size the SCF calculation gives me.
>
> I chose ecut=5 because I just wanted to make a fast example.
>
> The following WARNING appear on the output file at the end of the last 3
> datasets:
>
> Total localisation tensor (bohr^2) in cartesian coordinates
>   WARNING : still subject to testing - especially symmetries.
>       direction              matrix element
>    alpha     beta       real part   imaginary part
>      1        1       0.3676138062    0.0000000000
>      1        2       0.0000000000    0.0000000000
>      1        3       0.0000000000    0.0000000000
>      2        1       0.0000000000    0.0000000000
>      2        2       0.0000000000    0.0000000000
>      2        3       0.0000000000    0.0000000000
>      3        1       0.0000000000     0.0000000000
>      3        2       0.0000000000    0.0000000000
>      3        3       0.0000000000    0.0000000000
>
>   WARNING : Localization tensor in reciprocal space incomplete,
>             transformation to cartesian coordinates may be wrong.
>
>
>
> The input file is the following(I also attached it):
>
> #Prepare the computation of linear and non-linear optic properties
> #of GaAs crystal : ground-state with few bands,
> #then non-SCF with a larger number of bands, then ddk for different
> directions
> #Note that the k point sampling shoud be finer for significant results.
> The cut-off energy is also too low.
>
> ndtset 5
>
> #First dataset : SC run with kpoints in the IBZ
>    iscf1  3
>   nband1  42
>   nstep1 200
> 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 68  ! This number of bands might be too low for non-linear
> optics and real part of linear optics
>    nstep2 200
>   getwfk2  1   getden2 1   ! Usual file handling data
>
>
> #Third dataset : ddk response function along axis 1
>    iscf3 -3
>   nband3 68
>   nstep3  1  nline3  0
>    nqpt3  1  qpt3  0.0d0 0.0d0 0.0d0
>   rfdir3  1 0 0
> rfelfd3  2
> getwfk3  2
>
>
> #Fourth dataset : ddk response function along axis 2
>    iscf4 -3
>   nband4 68
>   nstep4  1  nline4  0
>
>    nqpt4  1  qpt4   0.0d0 0.0d0 0.0d0
>   rfdir4  0 1 0
> rfelfd4  2
> getwfk4  2
>
> # Fifth dataset : ddk response function along axis 3
>    iscf5 -3
>   nband5 68
>   nstep5  1  nline5  0
>
>    nqpt5  1  qpt5  0.0d0 0.0d0 0.0d0
>   rfdir5  0 0 1
> rfelfd5  2
> getwfk5  2
>
> #########################################################################
> #Data common to all datasets#############################################
> #########################################################################
>
> nsym 0
> kptopt 0
> nkpt 1
> kpt 0.0d0 0.0d0 0.0d0
>
> acell  43 44 38
> rprim   1.0     0.0   0.0
>         0.0     1.0   0.0
>         0.0     0.0   1.0
>
> #Definition of the atom types
> ntypat 3
> znucl 6 7 1
>
>
> #Definition of the atoms
> natom   24
> typat   1 1 1 1 1 1 1 1 1 1 1 1
>         3 3 3 3 3 3 3 3 3 3 2 2
>
> tolwfr  1.e-20
> nbdbuf 2
>
> #Definition of the planewave basis set
> ecut 5         # Maximal kinetic energy cut-off, in Hartre
>
> diemac 1.5
> diemix 0.5
>
>
> xcart    0.12610908E+02    0.69923842E+01    0.10268339E+02
>     0.15207306E+02    0.74174076E+01    0.10386263E+02
>     0.16167274E+02    0.98948730E+01    0.10484650E+02
>     0.14489426E+02    0.11953405E+02    0.10343192E+02
>     0.11894070E+02    0.11510622E+02    0.10175298E+02
>     0.10942651E+02    0.90405743E+01    0.10160446E+02
>     0.18112287E+02    0.13367950E+02    0.15093961E+02
>     0.17969181E+02    0.15296873E+02    0.16887708E+02
>     0.19363503E+02    0.17526713E+02    0.16588913E+02
>     0.20959827E+02    0.17804747E+02    0.14499162E+02
>     0.21158066E+02    0.15864730E+02    0.12730375E+02
>     0.19691041E+02    0.13660835E+02    0.12973277E+02
>     0.89148169E+01    0.87156412E+01    0.10023436E+02
>     0.16544236E+02    0.58533533E+01    0.10372034E+02
>     0.15204634E+02    0.13878773E+02    0.10327155E+02
>     0.10597717E+02    0.13104246E+02    0.10043308E+02
>     0.11890805E+02    0.50646308E+01    0.10204072E+02
>     0.16761223E+02    0.15060892E+02    0.18538351E+02
>     0.22094006E+02    0.19508725E+02    0.14280691E+02
>     0.22468742E+02    0.15993571E+02    0.11149587E+02
>     0.17030923E+02    0.11640529E+02    0.15354660E+02
>     0.19238302E+02    0.19020122E+02    0.17999518E+02
>     0.18892502E+02    0.10035037E+02    0.10276291E+02
>     0.20327037E+02    0.11703030E+02    0.11172947E+02
>
> ####################################################################
>
>
>
> Best wishes.
> Tonatiuh
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>
>
>
>
>
>
> --
> Pierre-Matthieu Anglade
>
>
>
> Sincerely.
> Yong Liu
>
> ---------------------------------
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