Doubt Regarding Renormalization Factor

[Bruno]

Hello!

My doubt is quite simple I suppose, I recently started doing some BSE calculations and I've finished the tutorials and so on. I noticed that its possible to perform scissor shifts and also renormalization of the bands on the BSE inputs. So my doubts are as follows:

- Is the scissor value of the BSE input just the pure difference between the QP gap and the DFT gap?

- I noticed that the output of the G0W0 calculation actually gives me the real and imaginary parts of a renormalization factor, how can I use these two values to deduce the ones that I should fill on the BSE input?

Thank you very much in advance!
Regards,

[Daniele Varsano]

Dear Bruno,

- Is the scissor value of the BSE input just the pure difference between the QP gap and the DFT gap?

Yes,

I noticed that the output of the G0W0 calculation actually gives me the real and imaginary parts of a renormalization factor, how can I use these two values to deduce the ones that I should fill on the BSE input

Renormalization factor it is used to calculate GW correction as first order expansion around the KS eigenvalues, it does not enter at all in the BSE input.
Besides the scissor value, if needed, you want to add a valence/conduction stretching.
In order to evaluate the stretching you can plot the Eqp vs Eks and calculate the slope with a simple linear fit.

Best,

Daniele

[Bruno]

Hello!

Thank you very much!

Regards,