Coherent & Incoherent contributions

[sitangshu]

Dear Sir,

Can you please tell me how/where can I get the data (which column and file) of the coherent and incoherent contributions of the excitonic eigenvalues in my BSE computation.
Just to let you know, I have already done the BS using e-ph interaction together with additional g^2F(w) calculations. The non-radiative excitonic linewidths are also acquired from BSE.

Additionally, I also want to know where I can get the data of Real and Imaginary parts of the Fan self energy.

Regards,
Sitangshu

[Daniele Varsano]

Dear Sitangshu,

I'm not sure I understand correctly your question,
The excitonic eigenvalues can be visualised after diagonalization (not iterative procedures) by running the ypp post processing:
ypp -e s
You will have a sorted file displaying exciton index and energies.

Best,
Daniele

[sitangshu]

Dear Daniele,

Actually I have solved the BSE using diagonalization technique and obtained the exitonic energies using the ypp. A suitable scissor and stretching is also used. In addition to this, the polaronic correction at a finite temperature (electron-phonon) is also made to read by relaxing the on the mass shell approach.
Now, I am curious to see what actually build these excitons. Is it coming from individual electron-hole interacting with lattice vibration or a coherent mechanism is there. That is, I am asking about Eq. 6 and Eq.7 in the paper by A. Marini: PRL 101, 106405 (2008). How can I get the 1st and 2nd individual terms of Eq. 6 and Eq.7?
and,
In order to see the same result using OMS and its validity, I need to see how far the pole of the Real and Im Fan self energy is from the bare energy at any n,k.

Please suggest, the way out...

Regards,
Sitangshu

[Daniele Varsano]

Dear Sitangshu,
I order to recognise the electron-hole contributing to the exciton you can use again the ypp utility.
Ypp -a to build the input file, where you select the exciton you want to analyse.
This will work only if the eigenstate of the BSE have be printed in a database, which is not done by default, and you need to activate the

Code: Select all

WRbsWF

variable in the diagonalization input file.
About the lattice vibration contribution unfortunately I cannot help you more, as I never did this kind of calculations.
Probably Andrea Marini can help you on that, but I think he's actually on holiday for the next days.
Best,
Daniele

[sitangshu]

Dear Daniele,

Thanks for your reply. Fortunately, I already activated the "WRbsWF"
I will wait for Prof. Andrea's suggestion for that... I will ping this on January 1st week. Hopefully he will return by that time. Are you people arranging any workshop on Yambo... I missed the April one

Regards,
Sitangshu

[Daniele Varsano]

Dear Sitangshu,
we use to organise a Cecam school every two years, so the next one in 2019.
In any case it is not a strike rule, and I cannot exclude we could organise a school also this year,
as usual all depends on the possibility to raise some funding. If this will be the case the school will be advertised
on the website, psi-k mailing list and linkedin (https://www.linkedin.com/company/5251401/)

Happy new year,

Daniele

[sitangshu]

Dear Daniele,

A very prosperous and happy new year to you, Alejandro and all of Yambo team.
Thanks for your response and information. I will make sure to attend this time.
About my previous question of individually determination of coherent mechanism form BSE calculations: I think this can be explained from the bright-dark transitions... right?


Regards,
Sitangshu