Yambo Community Forum

Dear Developers,

I have a metallic system.
is that an option in the input file of g0w0 to mention the plasmon frequency??
or that is only in the optical inputs (e.g. rpa)?
is there any relation between plasmon frequency and the ppa-imaginary energy?
Is the Bosonic temperature very important for metallic systems?
since I have two jobs with two different Bosonic temperature and ppa-imaginary energies
"1- BoseTemp= -1.000000 eV but for the other one is BoseTemp= -0.03675 eV
2- PPAPntXp= 27.21138 eV but for the other one is PPAPntXp= 1.000000 eV"
with different results!!1

Best regards

Dear Samaneh,

is that an option in the input file of g0w0 to mention the plasmon frequency??

Yes, if with plasmon frequency you mean Drude contribution, it can have an effect in the calculation of the screening.

is there any relation between plasmon frequency and the ppa-imaginary energy?

PPA Imaginary frequency has not a physical meaning but it is used to model the dynamical behaviour of the sceening with a single pole.
Usually for metals this does not apply or at least has to be verified.

Is the Bosonic temperature very important for metallic systems?
since I have two jobs with two different Bosonic temperature and ppa-imaginary energies
"1- BoseTemp= -1.000000 eV but for the other one is BoseTemp= -0.03675 eV
2- PPAPntXp= 27.21138 eV but for the other one is PPAPntXp= 1.000000 eV"
with different results!!

See this post for the meaning of the Bose temperature,
anyway the different results most probably comes from the very different use of the PLasmon frequency.

Best,
Daniele

Dear Daniele,
Thank you for your quick reply.
1-But when I use yambo -g n -p p -V all I can not find the Drudeterm in the input??
while it appears when running for rpa or bse!

Best regards
Samaneh

You're right.
It has been disactivated. I will check and reply to you.
Best,
Daniele

Ok thank you.
I am waiting for it.
I am using yambo version 3.4.1!

Best regards
Samaneh

Dear Samaneh,
Actually the Drude contribution it is not present when calculating Plasmon-Pole screening.
Most probably as it has not been tested. Anyway as I was telling you before, plasmon-pole usually it is not a good approximation for metalli systems.
Best,
Daniele

Dear Daniele,

Thanks a lot.
But why ppa is not a good approximation for metallic systems
since plasma frequency is for metals and ppa uses that frequency
so it does not cause a big problem
and indeed I think we do not need to introduce this term in input file
since when we use ppa, by default it should consider the plasma frequency????

Best
Samaneh

Dear Samaneh,
because usually the dielectric components cannot be approximated with a "single" plasma peaks but they are much more structured.
Anyway you can try it, and see if the approximation is still reasonable.
Best
Daniele

Dear Daniele,

I've done yambo -g n for my metallic system
using Drudeterm
but I got NAN for Eqp (please see the attached file)!!!!
I saw the post
"viewtopic.php?f=14&t=1105&hilit=Bose&si ... 0&start=10"
that you said to change the file src/common/FREQUENCIES_coarse_grid.F
but should I do this?
since I could do yambo -g n -p p without any problem!!!

Best regards
Samaneh

Dear Samaneh,
I'm not sure that the problem here is the Drude term: looking the mirror of your input at the end of te output file it does not look to be recognized.
It seems that Drude term it is skipped when performing GW. We will look at that very soon.
Anyway, please post the report and standard output file. Let's see if we can spot the problem, otherwise we will need to reproduce the error.

Best,
Daniele