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["Alexandra Friedrich" <Friedrich@kristall.uni-frankfurt.de>]

Dear ABINITioners,

 

can anyone help me with the IFC code?

I have calculated several DDBs for a body-centred tetragonal symmetry (I -4 2 d), reduced to a primitive unit cell using brvltt -1. When setting up an IFC-input file, the program disclaims, that some perturbations are missing in the DDBs. I think, this might be correlated to a wrong symmetry interpretation. May anyone help me with the input file?

 

The ERROR message is:

 

 symdm9 : ERROR -
  Informations are missing in the DDB.
  In blok     5 the following element is missing :
  idir1,ipert1,idir2,ipert2=   1   4   1   4
  Action : add the required information in the DDB,
  or modify your input file.

 

 

blok 5 corresponds to the q-vector 0.25 0.0 0.0

 

 

The common input variables of the unit cell, which I used for the calculation of the DDBs, are:

 

################################################

#Definition of the unit cell

spgroup 122

acell 10.92502 10.92502 20.190416

brvltt -1

#Definition of the k-point grid

ngkpt 4 4 4

nshiftk 1

shiftk 0.0 0.0 0.0

#Definition of the atom types

ntype 3

zatnum 47 31 34

#Definition of the atoms

natom 8

natrd 3

type 1 2 3

xred

0.000000000000 0.000000000000 0.000000000000

0.000000000000 0.000000000000 0.500000000000

0.2869178 0.25 0.125

nband 26

##################################################

 

Within the DDB, the reduced primitive cell is handled, with the parameters:

 

     natom         8
     acell  0.10000000000000D+01  0.10000000000000D+01  0.10000000000000D+01
     rprim -0.54625100000000D+01  0.54625100000000D+01  0.10095208000000D+02
            0.54625100000000D+01 -0.54625100000000D+01  0.10095208000000D+02
            0.54625100000000D+01  0.54625100000000D+01 -0.10095208000000D+02
      xred  0.00000000000000D+00 -0.10408340855861D-16  0.00000000000000D+00
            0.50000000000000D+00  0.50000000000000D+00  0.00000000000000D+00
            0.37500000000000D+00  0.41191780000000D+00  0.53691780000000D+00
            0.16191780000000D+00  0.62500000000000D+00  0.36917800000000D-01
            0.75000000000000D+00  0.25000000000000D+00  0.50000000000000D+00
            0.25000000000000D+00  0.75000000000000D+00  0.50000000000000D+00
            0.87500000000000D+00  0.83808220000000D+00  0.46308220000000D+00
            0.58808220000000D+00  0.12500000000000D+00  0.96308220000000D+00

 

 

I used following IFC-input-file:

 

#########################

# ifc code

dieflag 1

ifcflag 1

asr 2

chneut 2

enunit 2

eivec 1

dipdip 0

ifcana 1

ifcout 20

natifc 3

atifc 1 2 3

brav 1

ngqpt 4 4 4

nqshft 1

q1shft 0.0 0.0 0.0

nph1l 11

qph1l 0.0 0.0 0.0 1.0

0.05 0.05 -0.05 1.0

0.1 0.1 -0.1 1.0

0.15 0.15 -0.15 1.0

0.2 0.2 -0.2 1.0

0.25 0.25 -0.25 1.0

0.3 0.3 -0.3 1.0

0.35 0.35 -0.35 1.0

0.4 0.4 -0.4 1.0

0.45 0.45 -0.45 1.0

0.5 0.5 -0.5 1.0

#########################

 

I also tried several possibilities with 'brav 3'.

 

I would very much appreciate your help.

 

Alexandra Friedrich