Yambo Community Forum

Hello,

I have tried TD-RPA calculation with truncated Coulomb potential. I got the results for polarizability.

1)When I look at the output for polarizability, both imaginary/real parts of the alpha are zero. What do the last two columns stand for? Did I do something wrong in the input file of RPA calculation? I have attached the necessary output and input files for the calculation I did.

2) How do we get the optical spectrum from the alpha?
3)How do we compare the results with and without cutoff?

Thanks in advance!

Dear Niranji Ekanayake,

1) Columns 2 and 3 are zero likely because of a bug in yambo 5.1.0 which was later fixed. Try 5.1.2.
See here for the policy: https://github.com/yambo-code/yambo/wik ... gz-format)

2) alpha contains the 2D polarizability which describes the optical spectrum in 2D materials.

3) you can try to run with and without cutoff and compare the results. Without cutoff (you need to set NonPDirs="xy" in input) you should see the effect of the interaction with the replica.

Best,
D.

Hello Davide,
Thank you for the reply! I really appreciate it.

1) Columns 2 and 3 are zero likely because of a bug in yambo 5.1.0 which was later fixed. Try 5.1.2.
See here for the policy: https://github.com/yambo-code/yambo/wik ... gz-format)

Will try with new version.

2) alpha contains the 2D polarizability which describes the optical spectrum in 2D materials.

Are there any equations/ definitions that I can refer to since I am really new to this area? How does it relate to optical absorbance (If I want to plot Absorption vs. Energy)?

Thanks in advance!

For example you can have a look to these papers:
https://journals.aps.org/prb/abstract/1 ... .84.085406
https://pubs.acs.org/doi/10.1021/acs.nanolett.9b02982

Best,
D.

Hi Davide,

Thanks for the suggested papers.
My question is how I can get the absorbance data from the alpha(polarizability) calculated by Yambo. I want to get the spectrum for optical absorbance vs. energy.
Thanks in advance!

Niranji

Dear Davide,

Davide Sangalli wrote: ↑Thu Aug 24, 2023 10:50 pm Dear Niranji Ekanayake,

1) Columns 2 and 3 are zero likely because of a bug in yambo 5.1.0 which was later fixed. Try 5.1.2.
See here for the policy: https://github.com/yambo-code/yambo/wik ... gz-format)

As you mentioned I tried the calculation with yambo 5.1.2. Still, I am getting zero for both imaginary and real parts of alpha. Here I attached results. Could you please help me to figure out the problem here?

Thanks in advance.

Niranji

Dear Niranji,
can you try using the latest version of the code 5.2 (starting by scratch):
https://github.com/yambo-code/yambo
If the problem persists, please report here and we will try to reproduce your problem.
Best,
Daniele

Daniele Varsano wrote: ↑Mon Sep 11, 2023 11:16 am Dear Niranji,
can you try using the latest version of the code 5.2 (starting by scratch):
https://github.com/yambo-code/yambo
If the problem persists, please report here and we will try to reproduce your problem.
Best,
Daniele

Hi Daniele,
I have already tried different versions of Yambo for this system. It gives the same issue. Could you please try to reproduce the issue and kindly help me to fix the problem?

Best
Niranji

Dear Niranji,
in order to reproduce your problem, can you post your scf/nscf and eventually psuedo files?
Best,
Daniele

Daniele Varsano wrote: ↑Tue Sep 12, 2023 8:28 am Dear Niranji,
in order to reproduce your problem, can you post your scf/nscf and eventually psuedo files?
Best,
Daniele

Hi Daniele,
Thanks for the quick reply!
Here I attached the required files for the calculation. Thanks
Niranji