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["Anglade Pierre-Matthieu" <anglade@gmail.com>]

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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