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Re: questions about the results of BSE calculations?
Posted: Sat Feb 04, 2023 9:09 am
by pyadav
Dear team Yambo,
Can someone please comment on the following two points?
1. How can I convert the RL numbers (wavevectors for energy ) into Rydberg. Any formula or any rough estimation method?
2. The dipole socillator strength reported in file 'o.exc_qpt1_E_sorted' is absolute or relative to the largest dipole oscillator strength?
Thank you,
Pushpendra
Re: questions about the results of BSE calculations?
Posted: Mon Feb 06, 2023 10:28 am
by Daniele Varsano
Dear Pushendra,
1) the relation is Number of RL such that G^2/2 < Ecut. I do not have a rough estimation. Anyway, when you assign an energy cutoff you have the number of RL in the report. Please note that instead of Ha, or Ry, you can also use mHa (mRy).
2) They are normalized and you have the normalization factor at the top of the output file:
If you want to change it you can modify the source in ./ypp/excitons/excitons_sort_and_report.F
setting:
Best,
Daniele
Re: questions about the results of BSE calculations?
Posted: Mon Feb 06, 2023 1:36 pm
by pyadav
Dear Daniele,
Thank you so much for the reply and clarifications. They are really helpful.
Wishes,
Pushpendra.
Re: questions about the results of BSE calculations?
Posted: Thu Aug 17, 2023 3:28 am
by Dean
Dear Daniele,
After setting "Weight_treshold=0.0 eV", I get all the transitions in the file xxx.exc_qpt1_weights_at_1.
But I find that the weights for one K point in the first part of outfile do not equal the sum of weights in the second part of outfile, such as Gamma point (0.144) vs (0.02+......).
Please see the attached file.
Best wishes,
Re: questions about the results of BSE calculations?
Posted: Fri Aug 25, 2023 9:35 am
by Daniele Varsano
Dear Yimin,
this is just because the weight reported summed up on transitions for each K point and the individual contributions are normalized differently, i.e. the K point contribitions are normalized to its maximum:
see line 154 in
ypp/excitons/excitons_amplitudes.F
Code: Select all
148 K_weight=0._SP
149 do neh = 1,BS_H_dim
150 ikbz = BSS_eh_table(S_indx(neh),1)
151 ikibz = Xk%sstar(ikbz,1)
152 K_weight(ikibz)=K_weight(ikibz)+A_weight(neh)
153 enddo
154 K_weight=K_weight/maxval(K_weight)
155 titles(1:4)=(/' ','K-point [iku]',' ','Weight '/)
156 call msg('o weight','#',titles(:4),INDENT=0,USE_TABS=.true.)
157 do ikibz=1,Xk%nibz
158 if (K_weight(ikibz)>EXCITON_weight_treshold) then
159 call msg('o weight','# ',(/Xk%pt(ikibz,:),K_weight(ikibz)/),INDENT=0,USE_TABS=.true.)
160 endif
161 enddo
162 call msg('o weight','#','',INDENT=0,USE_TABS=.true.)
Indeed, they do not sum-up to 1, but they indicate that:
# : 0.375000000 0.714285672E-1 0.00000000 1.00000000
has the maximum contribution.
Best,
Daniele
Re: questions about the results of BSE calculations?
Posted: Mon Aug 28, 2023 10:00 am
by Dean
Dear Daniele,
Thanks for your reply.
Best,