selecting specific Q points

[m.abasifard]

Hello

I'm trying to calculate EELS for finite values of Q points. I have about 4000 Q point and I want to calculate EELS for some Q points to cover a wide range. As I've checked specifying the QpntsRxd from 1 to 4000 leads to calculating EELS not for all the Q ponits but for lots of Q points with a small step.I want to increase this step. How can I do this? Or in other words how can I select specific Q points?

Best regards,
Mostafa

[Daniele Varsano]

Dear Mostafa,
I'm not sure I understood your question:
you can calculate the eels for all the q points you have accordingly your k-point sampling.
The variable to control it is indeed QpntsRxd:

Code: Select all

%QpntsRXd				
1|5|		#	(Xd)	Transferred momenta
%

this for example do the calculation from the 1st to the 5th q points. The relation between indexes and q-point is reported in the r_setup and in all the reports.
If you want select a specific q-point, e.g. number 120, you can use:

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%QpntsRXd				
120|120|		#	(Xd)	Transferred momenta
%

Hope it helps,
Best,
Daniele

[m.abasifard]

Dear Daniele
Thank you very much for the reply. It really helps and I can do what I've wanted following your advice.
Just for clarification and to make me sure that there is no other way to do this, I should explain that:
When I set the QpntsRxd as the below:

Code: Select all

% QpntsRxd
   1| 4000|    #   (Xd)   Transferred momenta
%

the yambo calculates the EELS for q=1,49,142,235,328,... . The noticeable point is the value of Q points grows with a small step about 0.01 .
and now my question is, is it possible to increase value of the step and make yambo calculate EELS for e.g q=1,235,... (in a single run)?
or in other words can I make yambo calculate EElS for 5 specific (and not consecutive) Q points in a single run?

Best,
Mostafa

[Daniele Varsano]

Dear Mostafa,
actually it is not possible to do what you aim in a single run, but you can easily write a simple script producing different inputs with the sought q points and run them in succession.

Best,
Daniele