How to obtain absorption coefficient

[Zafer Kandemir]

Dear Developers,

I study 2D systems. First, I calculate the GW then BSE. I obtain o-md.alpha_q1_diago_bse, o-md.eel_q1_diago_bse and o-md.eps_q1_diago_bse files. How to obtain absorption coefficient and what is the unit?

Best regards.
Zafer

I added the Yambo input file.

[Daniele Varsano]

Dear Zafer,
depending on what you want to calculate you can do it from the real and image part of eps and/or alpha.
eps has not unit by definition. alpha it is given in atomic unit so it is [au]^3

Best,
Daniele

[Zafer Kandemir]

Dear Daniele,

Thank you for replying. I obtained the absorption coefficient I(w) by using eps1 and eps2 with the attached equation (J. Mater. Chem. A, 2013, 1, 2231–2237) . Am I doing it right?

Zafer

[Daniele Varsano]

Dear Zafer,
I do not know exactly wha you want to calculate, from eps1 and eps2 you can extract refractive indexes, extinction coefficients etc.
You can have a look to this chapter by M. S. Dresselhaus

http://web.mit.edu/course/6/6.732/www/6.732-pt2.pdf

In particular Section 1.3

Best,
Daniele