Linear response calculation

[Akash]

Dear Developers and all users,

I have to perform a linear response calculation to the external electric field. Please help me solve my two doubts-

1.) Do linear response calculations are referred to as real-time simulations. What exactly are real time simulations and how do they differ from normal simulations?
2.) Please throw some light on how would I perform a linear response calculation.

Regards

[Daniele Varsano]

Dear Akash,

1.) Do linear response calculations are referred to as real-time simulations. What exactly are real time simulations and how do they differ from normal simulations?

usually, linear response calculation are performed in frequency domains.

2.) Please throw some light on how would I perform a linear response calculation.

It depends from what level of theory you are interested in performing your calculations:
In the yambo tutorial pages (https://www.yambo-code.eu/wiki/) you can find tutorials on linear response (RPA, TDDFT, BSE..).

Best,
Daniele

[Akash]

Dear Danele,

I want to do a RPA calculation of linear and non-linear responses to the electric field. Can you please guide me through the code for the generation of the input file,?
Also, I have this doubt after reading some tutorials, that in the output of these calculations, how would I attribute the effects of the field, by plotting a graph or by calculating the value of some response function?

Regards.

[Daniele Varsano]

Dear Akash,

you can have a look at the Yambo cheatsheet, in slides 6-9 you have the theory of what yambo calculates and an overivew of the variable to be converged:
https://www.yambo-code.eu/wiki/index.php/Cheatsheets

here a tutorial for an RPA calculation:
https://www.yambo-code.eu/wiki/index.ph ... tandalone)

In the output you have the absorption spectrum considering and neglecting (IP) local fields, ie the response of the system to the perturbing electring filed along the direction you choose in input given by the LongDrXd variable.

Best,

Daniele