Gw+bse optical properties

[mjakhar7665]

Hello Sir,
I calculate the gw band gap and then i want to calculate the optical spectra with BSE+Gw but i get an error.
I search about it many times but i din't get any solution to that.
Can you check my parameters for gw and bse calculation is right ? and the result is good.

Can you help me in this regard
Mukesh
CEntral University of Punjab
India
Here is my attached file for gw and Bse

[Daniele Varsano]

Dear Mukesh,
note you can insert your signature in your user profile in order to avoid to repeat it in each post.
Coming to your questions, there are 2 issues:
1)

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% BSEBands
   1 | 200 |                   # [BSK] Bands range
%

This is an extremely high number of bands for BSE, this will end up in enormous matrix nc*nv*nk dimension, that probably will not fit the memory of your machine. Usually BSE converges considering few valence and few conduction bands across the gap. You can start with few bands and increase them until convergence.

2)
Looking at your log files:

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P1: [ERROR] STOP signal received while in :[06] Bethe Salpeter Equation @q1
P1: [ERROR]USER parallel structure does not fit the current run parameters. 10 CPU for 6 elements (ROLE is 'eh'

I suggest you to use a parallelisation scheme assigning CPU to k points as much as possibile, something like:

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BS_CPU= "20 1 1"             # [PARALLEL] CPUs for each role
BS_ROLEs= "k eh t"           # [PARALLEL] CPUs roles (k,eh,t)

Finally note that if you have already calculated the screening for the GW, yambo can read it so it is unnecessary to recalculate it in the BSE, you can remove form your input the em1s keyword and all the Xs variables.

Best,
Daniele