[Pw_forum] Phonons calcultation at Gamma

[Said Asma]

Dear QE users ans developers,  

I did the phonons calculation of the binary AlN (rocksalt)  with 16 atoms .

My output files is as following:

   Diagonalizing the dynamical matrix

     q = (    0.000000000   0.000000000   0.000000000 ) 

 **************************************************************************
     freq (    1) =       1.108833 [THz] =      36.986674 [cm-1]
     freq (    2) =       1.574620 [THz] =      52.523675 [cm-1]
     freq (    3) =       1.575398 [THz] =      52.549629 [cm-1]
     freq (    4) =       8.195754 [THz] =     273.380916 [cm-1]
     freq (    5) =       8.196815 [THz] =     273.416304 [cm-1]
     freq (    6) =       8.199734 [THz] =     273.513674 [cm-1]
     freq (    7) =       8.200351 [THz] =     273.534269 [cm-1]
     freq (    8) =       8.201724 [THz] =     273.580054 [cm-1]
     freq (    9) =       8.204042 [THz] =     273.657390 [cm-1]
     freq (   10) =       8.204069 [THz] =     273.658277 [cm-1]
     freq (   11) =       8.204305 [THz] =     273.666167 [cm-1]
     freq (   12) =       9.560810 [THz] =     318.914296 [cm-1]
     freq (   13) =       9.561375 [THz] =     318.933138 [cm-1]
     freq (   14) =       9.564736 [THz] =     319.045240 [cm-1]
     freq (   15) =       9.565551 [THz] =     319.072451 [cm-1]
     freq (   16) =       9.568429 [THz] =     319.168422 [cm-1]
     freq (   17) =       9.569095 [THz] =     319.190663 [cm-1]
     freq (   18) =      12.351077 [THz] =     411.987578 [cm-1]
     freq (   19) =      12.431223 [THz] =     414.660977 [cm-1]
     freq (   20) =      12.439828 [THz] =     414.947983 [cm-1]
     freq (   21) =      12.782122 [THz] =     426.365702 [cm-1]
     freq (   22) =      12.796523 [THz] =     426.846069 [cm-1]
     freq (   23) =      12.854425 [THz] =     428.777481 [cm-1]
     freq (   24) =      12.908753 [THz] =     430.589665 [cm-1]
     freq (   25) =      12.916648 [THz] =     430.852986 [cm-1]
     freq (   26) =      12.923203 [THz] =     431.071665 [cm-1]
     freq (   27) =      12.940057 [THz] =     431.633836 [cm-1]
     freq (   28) =      12.951841 [THz] =     432.026913 [cm-1]
     freq (   29) =      13.043933 [THz] =     435.098776 [cm-1]
     freq (   30) =      13.090098 [THz] =     436.638683 [cm-1]
     freq (   31) =      13.091268 [THz] =     436.677691 [cm-1]
     freq (   32) =      16.509761 [THz] =     550.706361 [cm-1]
     freq (   33) =      16.566717 [THz] =     552.606181 [cm-1]
     freq (   34) =      16.587373 [THz] =     553.295203 [cm-1]
     freq (   35) =      16.640103 [THz] =     555.054089 [cm-1]
     freq (   36) =      16.658006 [THz] =     555.651280 [cm-1]
     freq (   37) =      16.692001 [THz] =     556.785223 [cm-1]
     freq (   38) =      19.936035 [THz] =     664.994532 [cm-1]
     freq (   39) =      19.939099 [THz] =     665.096767 [cm-1]
     freq (   40) =      19.940916 [THz] =     665.157356 [cm-1]
     freq (   41) =      19.955181 [THz] =     665.633197 [cm-1]
     freq (   42) =      21.966886 [THz] =     732.736442 [cm-1]
     freq (   43) =      21.984557 [THz] =     733.325899 [cm-1]
     freq (   44) =      22.013871 [THz] =     734.303712 [cm-1]
     freq (   45) =      22.697394 [THz] =     757.103583 [cm-1]
     freq (   46) =      22.729742 [THz] =     758.182599 [cm-1]
     freq (   47) =      22.771292 [THz] =     759.568539 [cm-1]
     freq (   48) =      22.788849 [THz] =     760.154171 [cm-1]
 ***********************************************************************

It has 16 atoms then we have 48 frequencies, 3 acoustic (which tend to 0) and 46 optical frenquencies, but how can I differentiate between longitudinal and transverse waves frequency?


with respectful regards

Said Asma

***********************************************
Said Asma, 
PhD. LMCN,
Faculté des sciences de Monastir,
Avenue de l'environnement 5019-Monastir,Tunisie
E-mail :saidasma1987 at yahoo.fr
***********************************************
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