luminescence calculation

[SAM]

dear user,
I have a problem with the luminescence calculation. By following the tutorials the last step causes me a problem the step where you have to obtain the luminescence from the yambo_ph -excph o command. when I compile it I get the error saying that the el-ph data is not found. While I executed the other previous steps successfully.

my second concern about the q2r.x calculation of quantum espresso. In the tutorials on the calculation of luminescence assisted by phonon, after the calculation of phonon it is necessary to calculate q2r.x, matdyn. however, before executing q2r you must have generated the dyn0 as well as the dyn* obtained from the phonon calculation. my question is how to generate the dyn0 in order to do the q2r.x calculation.

SAM
PhD Student at university of Lome

[claudio]

Dear SAM

I repeated all the steps of the tutorial and it works perfectly.
I used QE 7.2 and the Yambo version of the tutorial, and compiled them with gfortran.
Some additional comments:

1) in the original tutorial q2r.x is never used, please check the script run_dvscf.sh.
q2r.x is used only if you want to use the double-grid. I advice you to run the tutorial without double-grid
and then if you want you can add it.

2) I added the YamboDatabases including electron-phonon in the tutorial web page, you can download them if you want.
https://www.yambo-code.eu/wiki/index.ph ... minescence

best
Claudio

[SAM]

Dear claudio,
Thank you very much for your answer. The difficulty I encountered was that when I compiled the bash ./rundvscf: I encountered the error: ypp_ph: unrecognized option '-noopenmp'.
the difficulty compared to the q2r.x calculation was based on the phonon-assisted photoluminescence tutorials. It was necessary to calculate matdyn.x. to generate the Q.modes.
my second difficulty lies in the calculation of finite difference after obtaining the dipoles. is this done externally?

thanks
SAM
PhD student at university of Lome/Togo

[claudio]

Dear SAM

1) remove the option "-noopenmp" form the script run_dvscf.sh, but this is strage, if you do ypp_ph --help
do you see this option?

2) for the second tutorial
https://www.yambo-code.eu/wiki/index.ph ... placements
I will check it and let you know

best
Claudio

[SAM]

Dear Claudio,

Thank you for answering me .
when I compile ypp_ph I get *nompi*

I have a complaint about the tutorials on phonon-assisted luminescence. Is it possible to leave us a bash script which automates all the calculation up to the calculation of finite difference, as is done in the tutorials on luminescence. Because it seems a bit complicated to me. Maybe looking at the automated bash will help me.
THANKS
SAM
PhD student at University of Lome/Togo

[claudio]

Dear SAM

for the tutorial at finite differences, I fixed the wiki webpage, now you can download all inputs and run calculations
for phonons as explained in the tutorial, then run q2r.x

https://www.yambo-code.eu/wiki/index.ph ... transition

best
Claudio

[claudio]

You can remove also -nompi from the input,

regarding the automatic script I will have a look and let you know

best
Claudio

[claudio]

Anyway at the end of the tutorial all inputs are provided


https://www.yambo-code.eu/wiki/index.ph ... s_for_h-BN

[SAM]

Dear Claudio,

thank you very much for adding more detailed information to the tutorials, I think it's a bit clear for me.
My second question was: how is the difference calculated? Is this done externally?
is it possible to use yambopy to do this?
We will have a total of 12 dipoles with which we must calculate the finished difference.


SAM
PhD student at university of Lome/Togo

[claudio]

Dear SAM

first of all I added some additional script in the wiki

https://www.yambo-code.eu/wiki/index.ph ... placements

the derivative of dipoles are calculated in this way:
1) the lowest dipole are zero because the transition are indirect (in the unit cell)
2) when you displace atoms along a phonon mode you activate a dipole, this mean that the dipole that before was zero, not it is different from zero.
Therefore the derivative of the diple id d Dip/ d u = [ Dip(diplaced) - 0.0 ] / du
at the end you can take as derivative the value you obtain when you displace atoms. You should divide for "du" but it is just a multiplicative factor.

best
Claudio