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[GaoTao <gaotaoscu@hotmail.com>]

Dear Colleague,
 
When I use ABINIT to practise to reproduce the LO-TO splitting for ZnO "Pressure dependence of the lattice dynamics of ZnO: An ab initio approach, published on PHYSICAL REVIEW B 69,094306(2004)", I got into trouble at the assignment of vibrational mode for the LO-TO splitting.
 
I can assign the correct irreducible representation to Phonon frequencies when without LO-TO splitting, e.g.,for ZnO(spacegroup,No.186) there exists the relation 2A1+2B1+2E1+2E2 at the Brillouin-zone center (q=0), i.e.,
 
'  Phonon wavevector (reduced coordinates) :  0.00000  0.00000  0.00000
 Phonon energies in Hartree :
   0.000000E+00  0.000000E+00  0.000000E+00  3.799350E-04  3.799358E-04
   1.143489E-03  1.587916E-03  1.587917E-03  1.737701E-03  1.737703E-03
   1.747231E-03  2.422538E-03
 Phonon frequencies in cm-1    :
-  (0.000000E+00  0.000000E+00  0.000000E+00)A1+E1  (8.338610E+01  8.338626E+01)E2
-  (2.509668E+02)B1  (3.485072E+02  3.485076E+02)E1  (3.813812E+02  3.813816E+02)E2
-  (3.834728E+02)B1  (5.316857E+02)A1'
 
When approaching GAMMA center along some different direction in Brillouin-zone, the calcultion results indicate that there will have LO-TO splitting for some vibration mode, but I have no idea on how to assign these phonon frequencies to correct vibrational mode. My output file for this part is as follow,
 
'  Phonon at Gamma, with non-analyticity in the
  direction (cartesian coordinates)  1.00000  0.00000  0.00000
 Phonon energies in Hartree :
   0.000000E+00  0.000000E+00  0.000000E+00  3.799350E-04  3.799358E-04
   1.143489E-03  1.587916E-03  1.737701E-03  1.737703E-03  1.747231E-03
   2.149073E-03  2.422538E-03
 Phonon frequencies in cm-1    :
-  0.000000E+00  0.000000E+00  0.000000E+00  8.338610E+01  8.338626E+01
-  2.509668E+02  3.485072E+02  3.813812E+02  3.813816E+02  3.834728E+02
-  4.716670E+02  5.316857E+02
 
  Phonon at Gamma, with non-analyticity in the
  direction (cartesian coordinates)  0.00000  0.00000  1.00000
 Phonon energies in Hartree :
   0.000000E+00  0.000000E+00  0.000000E+00& nbsp; 3.799350E-04  3.799358E-04
   1.143489E-03  1.587916E-03  1.587917E-03  1.737701E-03  1.737703E-03
   2.422538E-03  2.522783E-03
 Phonon frequencies in cm-1    :
-  0.000000E+00  0.000000E+00  0.000000E+00  8.338610E+01  8.338626E+01
-  2.509668E+02  3.485072E+02  3.485076E+02  3.813812E+02  3.813816E+02
-  5.316857E+02  5.536868E+02
 
  Phonon at Gamma, with non-analyticity in the
  direction (cartesian coordinates)  0.00000  1.00000  0.00000
 Phonon energies in Hartree :
   0.000000E+00  0.000000E+00  0.000000E+00  3.799350E-04  3.799358E-04
   1.143489E-03  1.587917E-03  1.737701E-03  1.737703E-03  1.747231E-03
   2.149072E-03  2.422538E-03
 Phonon frequencies in cm-1    ; :
-  0.000000E+00  0.000000E+00  0.000000E+00&nbs p; 8.338610E+01  8.338626E+01
-  2.509668E+02  3.485076E+02  3.813812E+02  3.813816E+02  3.834728E+02
-  4.716668E+02  5.316857E+02'
 
I am quiet confused on whether the assignment of these phonon frequencies(along different directions) are same as q=0 without LO-TO splitting or not. Would you like to help me assign these Phonon frequencies to the correct vibrational modes? Any suggestion will be appreciated.
 
Thank you very much.
 
Best,
 
Tao
 
BTW, my files including log, input and output files are enclosed as attachment.

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Attachment: phonon.tar.gz
Description: Binary data