[Pw_forum] "Raman activities" do not converge

[xirainbow]

Dear Sanjeev:

> In my guess, the converging mostly depends on choosing pseudopotential,
         I  changes the pseudopotential from "C.pw-mt_fhi.UPF" to
"C.pz-hgh.UPF" and get the expected "Raman activity" for different ecutwfc.
         Thank you very much :)

         The following is my results.
Using "C.pw-mt_fhi.UPF" :
ecutwfc(Ry)      Freq(cm-1)          Raman activity(A^4/amu)
 65                 1330.65                   68.9754
100                1330.23                   68.9674
110                1330.50               3066.0811
120                1330.48                   15.1570
130                1330.47                   68.9545
140                1330.48                   68.9536
150                1330.48                   68.9541


Using  "C.pz-hgh.UPF" :
ecutwfc(Ry)      Freq(cm-1)          Raman activity(A^4/amu)
 70               1330.78                  69.6225
 90               1341.85                  70.0144
100              1333.32                  70.1650
110              1337.38                  87.7369
120              1339.90                  69.9051
130              1339.60                  69.9249
140              1338.35                  69.9469
150              1337.71                  69.9402


On Thu, May 30, 2013 at 12:43 AM, Sanjeev Gupta
<physics.skgupta at gmail.com>wrote:

> Dear Wang
>
> In my guess, the converging mostly depends on choosing pseudopotential, so
> may be it is the problem, that you are not getting converge Raman activity.
> Otherhand, can you check your structure as well as, but i am not sure.
>
> Best
> Sanjeev
>
>
> On Wed, May 29, 2013 at 5:22 AM, xirainbow <nkxirainbow at gmail.com> wrote:
>
>> Dear all:
>>             I calculated the "Raman activity" of diamond(Carbon) using
>> QE-5.0.
>>             The "Raman activity" changes too much with ecutwfc.
>>             Could you give me some help?
>>
>> Calculational results of "Raman activity variation with ecutwfc"
>> ("14*14*14 kmesh).
>>    ecutwfc(Ry)      Freq(cm-1)          Raman activity(A^4/amu)
>>    65                     1330.23                  68.9754
>>    100                   1330.65                  68.9674
>>    110                   1330.50              3066.0811
>>    120                   1330.48                  15.1570
>>    130                   1330.47                  68.9545
>>
>> The following is input of pw.x and ph.x:
>> INPUT of SCF:
>>  &control
>>     calculation='scf',
>>     disk_io='low',
>>     restart_mode='from_scratch',
>>     prefix='diamond.$i'
>>     pseudo_dir = '/home/lykong/hwang/espresso-5.0/pseudo',
>>     outdir='/home/lykong/hwang/tmp'
>>  /
>>  &system
>>     ibrav = 0, celldm(1) = 1.88972687777436, nat= 2, ntyp= 1,
>>     ecutwfc = $i
>>  /
>>  &electrons
>>     mixing_beta = 0.7
>>     conv_thr =  1.0d-8
>>  /
>> ATOMIC_SPECIES
>>  C   12.01   C.pw-mt_fhi.UPF
>> ATOMIC_POSITIONS {crystal}
>> C   0.000000000         0.000000000         0.00000000
>> C   0.250000000         0.250000000         0.25000000
>> CELL_PARAMETERS
>>    1.758613117   1.758613117   0.000000000
>>    1.758613117   0.000000000   1.758613117
>>    0.000000000   1.758613117   1.758613117
>>
>>
>> INPUT of PHONON:
>> phonons of diamond at Gamma
>>  &inputph
>>   tr2_ph=1.0d-14,
>>   alpha_mix=0.7
>>   prefix='diamond.$i'
>>   epsil=.true.,
>>   lraman=.true.,
>>   amass(1)=12.01,
>>   outdir='/home/lykong/hwang/tmp'
>>   fildyn='diamond.$i.dynG',
>>   reduce_io=.TRUE.
>>  /
>> 0.0 0.0 0.0
>>
>>
>>
>> --
>> ____________________________________
>> Hui Wang
>> School of physics, Fudan University, Shanghai, China
>>
>> _______________________________________________
>> Pw_forum mailing list
>> Pw_forum at pwscf.org
>> http://pwscf.org/mailman/listinfo/pw_forum
>>
>
>
>
> --
> With Best Regards,
>
> ------------------------------------
> Dr. Sanjeev Kumar Gupta
> Fulbright Post-Doctoral Scholar
> Dept. of Physics
> Michigan Technological University
> 1400 Townsend Drive, Houghton
> MI 49931, USA
> ------------------------------------
>
> _______________________________________________
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>



-- 
____________________________________
Hui Wang
School of physics, Fudan University, Shanghai, China
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