[Pw_forum] phonon Calculation

[Saied Md Pratik]

Dear Sir,
If I don't mention asr='zero-dim' in the input section then also I am not
getting the frequencies correctly. Now I am getting the following
frequencies

--------------------------------------
# mode   [cm-1]    [THz]      IR
    1   -132.06   -3.9590    0.1498
    2   -131.77   -3.9503    0.1486
    3   -109.35   -3.2782    0.0031
    4   -108.74   -3.2599    0.0032
    5     91.54    2.7443    0.0511
    6    127.22    3.8141    0.0142
    7    153.76    4.6095    0.0003
    8    164.03    4.9174    5.4586
    9    164.06    4.9185    5.4543
   10    190.74    5.7182    4.0762
   11    191.78    5.7493    0.0010
   12    191.95    5.7544    0.6314
   13    380.90   11.4192    0.0000
   14    395.35   11.8522    0.0004
   15    397.38   11.9132    0.0001
   16    410.55   12.3081    0.0022
   17    412.54   12.3677    0.0019
   18    420.67   12.6114    0.0001
   19   1398.48   41.9255    0.0328
   20   1407.66   42.2007    5.2353
   21   1408.10   42.2137    5.5635
   22   1414.41   42.4029    0.0151
   23   1414.84   42.4158    0.3427
   24   1435.81   43.0446    7.0296
   25   1635.17   49.0210    0.0000
   26   1666.27   49.9536    0.0000
   27   1685.50   50.5300    0.0001
   28   1686.11   50.5484    0.0000
   29   3052.32   91.5064    0.5011
   30   3066.46   91.9303    3.0260
   31   3082.41   92.4082   45.2275
   32   3086.97   92.5451   19.4732
   33   3091.92   92.6934   41.1318
   34   3095.54   92.8020   33.9297
   35   3103.29   93.0342   38.8619
   36   3154.67   94.5747   67.2231
--------------------------------------------------------------------

Thanking you.
Pratik



> On Fri, 2014-05-02 at 14:09 +0530, Saied Md Pratik wrote:
>
> > NH4Br crystal
>
> > asr='zero-dim'
>
> if it is a real crystal, you shouldn't use 'zero-dim'.
> If it is a molecule in a supercell, you may have unstable
> (and physically irrelevant) libration modes
>
> >    celldm(1) = 1.890359168
>
> putting into celldm(1) the a.u. to A conversion factor
> is a bad habit in my opinion, and ot doesn't make sense
> if you specify your cell vectors in A:
>
> > CELL_PARAMETERS angstrom
> >    5.633079685   0.000000000   0.000000000
> >    0.000000000   5.633079685   0.000000000
> >    0.000000000   0.000000000   3.982678150
>
> P.
>
> --
> Paolo Giannozzi, Dept. Chemistry&Physics&Environment,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
>
>
>
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