Exact meaning of Strength from sort_and_report

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Fadil
Posts: 56
Joined: Sun May 24, 2020 1:56 pm

Re: Exact meaning of Strength from sort_and_report

Post by Fadil » Sat Jun 25, 2022 2:09 pm

Dear Daniele,

I attached the report and log files of one of the bse calculation with the full diagonalization.
It seems working for more than 1 week, but still there is no progress. Does waiting any longer do any good?
Or do you have any suggestion (about parallelization or something else) to obtain results with this run?

Best
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Dr. Fadıl İYİKANAT
ICFO-The Institute of Photonic Sciences
Barcelona-SPAIN

Fadil
Posts: 56
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Re: Exact meaning of Strength from sort_and_report

Post by Fadil » Thu Jun 30, 2022 4:10 pm

Dear Daniele,

The slepc solver works great, but it only prints the dielectric function.
However, when we apply cutoff in 2D system we need to obtain polarizabilities.
Is it possible to obtain alpha when we use slepc.

Best
Dr. Fadıl İYİKANAT
ICFO-The Institute of Photonic Sciences
Barcelona-SPAIN

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Daniele Varsano
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Re: Exact meaning of Strength from sort_and_report

Post by Daniele Varsano » Mon Jul 04, 2022 9:45 am

Dear Fadıl,

slepc should also provide the alpha, can you post your input file?
About your previous run, your BSE matrix is large but still feasible with diagonalization, if it is stacked after 1 week it means something went wrong, but it is not easy to spot the reason.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

Fadil
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Joined: Sun May 24, 2020 1:56 pm

Re: Exact meaning of Strength from sort_and_report

Post by Fadil » Mon Jul 04, 2022 12:54 pm

Dear Daniele,

Yes, you are right. When I change the input file it provide the alpha also.
Thank you!

Best
Dr. Fadıl İYİKANAT
ICFO-The Institute of Photonic Sciences
Barcelona-SPAIN

Quxiao
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Joined: Fri Mar 26, 2021 11:27 am

Re: Exact meaning of Strength from sort_and_report

Post by Quxiao » Mon Apr 03, 2023 2:31 pm

Xiaoming Wang wrote: Tue Aug 10, 2021 4:22 pm Hi,

Another workaround, to get the exciton oscillator strength (transition dipole) I modified the code

Code: Select all

   ......
   ![--------------------------------------------
   n_elements=n_elements+1
   titles(n_elements)='dipole [Bohr^2]'
   !--------------------------------------------]
   Residuals(:) = real(BS_R(:)*conjg(BS_R(:)),SP)
   if (write_widths)  Residuals(:) = abs(BS_R(:))
   if(iq==1) q_norm=q0_def_norm**2
   if(iq> 1) q_norm=iku_v_norm(BSqpts(:,iq))**2
   ![--------------------------------------------------------------
   ! the oscillator strength
   dipol(:) = Residuals(:)/q_norm/(RL_vol/d3k_factor)
   !----------------------------------------------------------------]
   Residuals(:) = Residuals(:)*real(spin_occ,SP)/(2._SP*pi)**3*d3k_factor*4._SP*pi/q_norm*HA2EV
   .......
   ![------------------------------------------
   ! to print
   n_elements=n_elements+1
   rv(n_elements)=dipol(j2)
   !-------------------------------------------]
in ypp/excitons/excitons_sort_and_report.F.
Dear Xiaoming:
Thanks for your help!Could you know how to get the P_S^2 from the ypp?I changed the code based on your code,but the units of the P_S^2 let me confused!
Best wishes!
Quxiao
Quxiao in BIT,calculate the exciton

nilesh12
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Joined: Sun Feb 18, 2024 4:31 pm

Re: Exact meaning of Strength from sort_and_report

Post by nilesh12 » Mon Feb 26, 2024 4:39 pm

Dear all
please clarify my point that the strengths are reported in this file are in unit of 'eV' or unit of 'e.bohr'.



Maximum Residual Value = 0.99184E+00

E [ev] Strength Index

2.66076220 0.595841334E-8 1.00000000
2.66377698 0.432214064E-3 2.00000000
2.66379905 0.209940922E-2 3.00000000
2.66782112 0.966402438E-3 4.00000000
2.66784263 0.949996735E-3 5.00000000
2.67358023 0.143271606E-8 6.00000000
2.69463200 0.342101391E-3 7.00000000
2.69464556 0.317773602E-3 8.00000000
2.70601855 0.303304590E-3 9.00000000
2.70622099 0.104622693E-2 10.0000000
2.70629461 1.00000000 11.0000000
2.70630689 0.864063373E-1 12.0000000
2.83036681 0.881903188E-3 13.0000000
2.83045742 0.118884024E-2 14.0000000
2.83504518 0.601130605E-1 15.0000000
2.83513491 0.592793722E-1 16.0000000
2.86564469 0.115701542E-6 17.0000000
Nilesh Kumar
University of Ostrava

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Daniele Varsano
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Re: Exact meaning of Strength from sort_and_report

Post by Daniele Varsano » Tue Feb 27, 2024 11:02 am

Dear Nilesh,

strengths are in Bohr, please note that they are normalized to the largest strength and renormalization factor is reported as Maximum Residual Value.

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

nilesh12
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Re: Exact meaning of Strength from sort_and_report

Post by nilesh12 » Tue Feb 27, 2024 8:07 pm

Dear Daniele
Thank you very much for your reply and the important suggestion regarding renormalization. But I was reading in previous post that the reported oscillator strengths are formed as square modulus of Residual |R|^2. So if I am not wrong the final unit is bohr^2?

And my second question is that I am trying to calculate BSE transition dipole moment (\mu^2) so should i use this relation,

\mu^2 = |R|^2 * Direct volume of the lattice * N_k / 4 pi * spin

please correct me is there anything wrong?

Thank you
Nilesh Kumar
University of Ostrava

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Daniele Varsano
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Re: Exact meaning of Strength from sort_and_report

Post by Daniele Varsano » Wed Feb 28, 2024 9:01 am

Dear Nilesh,

you are right, the strength is calculated as the square modulus.
About the prefactor, it should be correct, to be sure you can have a look at the epsilon expression in Eq.11a in the Yambo cheatsheet:
https://www.yambo-code.eu/wiki/images/c ... et-5.0.pdf

Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/

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