Response block size

Deals with issues related to computation of optical spectra in reciprocal space: RPA, TDDFT, local field effects.

Moderators: Davide Sangalli, andrea.ferretti, myrta gruning, andrea marini, Daniele Varsano, Conor Hogan

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samaneh
Posts: 165
Joined: Tue Jan 21, 2014 9:03 am

Response block size

Post by samaneh » Sat Sep 20, 2014 12:08 pm

Hello developers,
Would you please tell me what is the meaning of s in the followed variable:
NGsBlkXs
I run yambo -o b -k sex -y h and set the values of BSENGBlk and NGsBlkXp
parameters to the converged ones for yambo -g n -p p.
but I do not know the value of the NGsBlkXs parameter so I leave it with the
default value (NGsBlkXs= 1), is that right??
Best regards
S. Ataei, University of Tehran.
S. Ataei, PhD student at University of Tehran, Iran.

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Daniele Varsano
Posts: 4198
Joined: Tue Mar 17, 2009 2:23 pm
Contact:

Re: Response block size

Post by Daniele Varsano » Sat Sep 20, 2014 1:06 pm

Dear Samaneh,
s means "static", p means "pasmon pole":
BSE need static screening, and by default it calculates it when building the BSE kernel. Anyway if you calculated the plasmon pole database
before and you have the (n)db.pp in your save directory, it contains also the static dielectric matrix and you can build your input by:

Code: Select all

/yambo -o eh -k sex -p p -y h 
and remove by hand the em1s line in the beginning of the input. Otherwise you need to calculate the static screening and need to set NGsBlkXs to the same value of BSENGBlk. In any case if the run read the pp database or not it is written in the report check it, and check also
in

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[WR./SAVE//db.BS_Q1]
the

Code: Select all

 W |Interaction is diagonal :no
      |Matrix size             : 

if the matrix size is the one you put in input.

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/

samaneh
Posts: 165
Joined: Tue Jan 21, 2014 9:03 am

Re: Response block size

Post by samaneh » Sat Sep 20, 2014 1:35 pm

Dear Daniele,
Thanks for your quick reply.
I run yambo -o b -k sex -y h using the db.qp database of yambo -g n -p p
in the input file of yambo but I did not remove the em1s line, and also
as I mentioned I set the BSENGBlk and NGsBlkXp=400 RL
but NGsBlkXs=1, do you mean that it is right???
Thanks again.
S. Ataei, University of Teharn.
S. Ataei, PhD student at University of Tehran, Iran.

User avatar
Daniele Varsano
Posts: 4198
Joined: Tue Mar 17, 2009 2:23 pm
Contact:

Re: Response block size

Post by Daniele Varsano » Sat Sep 20, 2014 2:55 pm

I have already answered you,
Open the report file and check if the db.pp database has been read by yambo and if the matrix size of the screening "W" is what you requested, it is all reported. Note the db.QP does not have nothing to do with the screening .
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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