O.qp file columns reprents what?

Concerns issues with computing quasiparticle corrections to the DFT eigenvalues - i.e., the self-energy within the GW approximation (-g n), or considering the Hartree-Fock exchange only (-x)

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krishn
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Joined: Thu Oct 29, 2015 5:12 pm

O.qp file columns reprents what?

Post by krishn » Wed Nov 11, 2015 1:02 pm

Dear Developers,

In o.qp file what 'E' represents? is it quasi particle energy calculated? and is Eo the Kohn-Sham energy level for that particular band right
in file columns look like this

K-point Band Eo E-Eo Sc(Eo)
1 1 -21.15638 -6.73911 2.73347




Thanks and Regards,
K. Krishnaiah Setti
AcSIR, JRF
CSIR-SERC
Chennai
India

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Daniele Varsano
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Joined: Tue Mar 17, 2009 2:23 pm
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Re: O.qp file columns reprents what?

Post by Daniele Varsano » Wed Nov 11, 2015 1:34 pm

Dear Krishnaiah,
yes as you said:

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E0= HS energy
E= QP energy
E-E0 = QP correction
Sc = correlation part of the self energy
In o.qp file you find E0 and E-E0 values, so the QP energy will be column 3 + column 4.
If the QP values are read from an existing calculation you find directly E.
Anyway in the report you will find more information.

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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wachr
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Joined: Wed Sep 24, 2014 4:43 pm

Re: O.qp file columns reprents what?

Post by wachr » Wed Mar 30, 2016 9:25 am

Dear all,

just a comment on the answer - even if the post is a bit older: I sometimes experience output like

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#  K-point    Band       Eo         Eqp        E-Eo       Z
#
instead of

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#  K-point    Band       Eo         E-Eo       Sc(Eo)
#
The difference occurs only, I guess, if an old result of a previous run is reprinted by yambo. This gave me some confusion when plotting, as the difference between dft and gw was not understandable (E-Eo was in another column, then).

Kind regards,
Christian

P.S. edit: I removed some confusing numbers from the output.
Christian Wagner
Institute of Physics
Chemnitz University of Technology, Germany

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Daniele Varsano
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Re: O.qp file columns reprents what?

Post by Daniele Varsano » Wed Mar 30, 2016 9:31 am

Dear Christian,
yes, as you argued this happen if yambo read a previous compatible calculation, i.e. it will not calculate the QP correction, but just read and write it in the output.
You can see it by inspecting the report file: (search for RD for read databases and WR for written database). When a database is read yambo inspect the parameters and see if they are compatible with the one of the input file. Depending on which parameter differs it can just give a warning or an ERR. In the latter case it recalculate the correction.
In order to plot them, the only think to do is to pay attention to the right column.

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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