[Pw_forum] "Raman activities" do not converge

[Sanjeev Gupta]

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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