[QE-users] About Phonon calculations, is it possible to calculater lraman (Raman) without calculating the the repentation Self-consistent Calculation again, it is a lot of cost.

[ludwigboltzmann.sc10 at nycu.edu.tw]

 Dear Prof.Kumar,
Sure, I do not need to run scf again.
However, is it possible to calculate this Raman tensor only?
I saw in the PHonon developer manual:
3) In a recover run check what is already available on the .xml files and sets the appropriate done flags to .TRUE. 
4.9) Compute Raman tensor and SD


Sincerely,
National Yang Ming Chiao Tung University
HY Lu


    在 2023年10月30日 星期一 下午05:12:18 [GMT+8]， Ramesh Kumar Kamadurai<rkamadur at gitam.edu> 寫道：  
 
 Yes you can start phonon calculation with different sets of parameters using the same *wfc file. It is not necessary to redo scf calculation. But recover=.true (Phonon recovery) option may not be possible for this case because you intend to change the parameter for your new calculation. Hope this helps.

Best regards,

K. Ramesh Kumar

 Assistant Professor 

Gandhi Institute of Technology and Management, 

 Phone: +91 9895637981, +1 6782419790 

Email: kraamesh57 at gmail.com rkamadur at gitam.edu

On Mon, Oct 30, 2023 at 12:14 PM ludwigboltzmann.sc10 at nycu.edu.tw <ludwigboltzmann.sc10 at nycu.edu.tw> wrote:

Dear users:

I am going to calculate do phonon calculation and Raman spectra calculation of my perovskite(only at Gamma point), 
My procedure is like this: doint: vc-relax & scf→phonon calculation→dynmat
#phononphonon calculation for diamondg(Only gamma pt).  !use QEsub_ph (ph.x) (rather than pw.x)&inputph  outdir="output"  prefix = ' perovskite',  tr2_ph = 1.0d-14               !Threshold for self-consistency  ldisp = .false  asr = .true  zue = .true  epsil = .true  trans = .true         fildyn = ' perovskite.dyn'  start_q = 1  last_q = 1  "lraman = .true."  recover = .true !start from old/0 0 0                            !gamma pt
I made a mistake without adding  "lraman = .true.", so I got dynmat.out with only IR but without Raman activities. 
Is it possible to calculater lraman (Raman) without calculating the repentation Self-consistent Calculation  again, it is a lot of cost.

Representation #   1 mode #   1
     Self-consistent Calculation
      iter #   1 total cpu time : 21284.5 secs   av.it.:   5.0      thresh= 1.000E-02 alpha_mix =  0.700 |ddv_scf|^2 =  6.481E-09
      iter #   2 total cpu time : 21666.4 secs   av.it.:  17.0      thresh= 8.051E-06 alpha_mix =  0.700 |ddv_scf|^2 =  1.068E-08
      iter #   3 total cpu time : 22023.4 secs   av.it.:  16.0      thresh= 1.033E-05 alpha_mix =  0.700 |ddv_scf|^2 =  3.855E-10
      iter #   4 total cpu time : 22379.9 secs   av.it.:  16.0      thresh= 1.963E-06 alpha_mix =  0.700 |ddv_scf|^2 =  1.560E-11
      iter #   5 total cpu time : 22749.5 secs   av.it.:  16.9      thresh= 3.950E-07 alpha_mix =  0.700 |ddv_scf|^2 =  1.517E-12
      iter #   6 total cpu time : 23124.2 secs   av.it.:  17.0      thresh= 1.232E-07 alpha_mix =  0.700 |ddv_scf|^2 =  1.771E-13
      iter #   7 total cpu time : 23504.1 secs   av.it.:  17.0      thresh= 4.208E-08 alpha_mix =  0.700 |ddv_scf|^2 =  2.903E-14
      iter #   8 total cpu time : 23890.4 secs   av.it.:  17.9      thresh= 1.704E-08 alpha_mix =  0.700 |ddv_scf|^2 =  1.027E-14
      iter #   9 total cpu time : 24267.0 secs   av.it.:  17.0      thresh= 1.013E-08 alpha_mix =  0.700 |ddv_scf|^2 =  5.001E-15
     End of self-consistent calculation
     Convergence has been achieved 

Sincerely,
National Yang Ming Chiao Tung University
HY Lu
_______________________________________________
The Quantum ESPRESSO community stands by the Ukrainian
people and expresses its concerns about the devastating
effects that the Russian military offensive has on their
country and on the free and peaceful scientific, cultural,
and economic cooperation amongst peoples
_______________________________________________
Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
users mailing list users at lists.quantum-espresso.org
https://lists.quantum-espresso.org/mailman/listinfo/users
  
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20231030/02f16971/attachment.html>