Yambo Community Forum

Hello,

I have tried to TDDFT-ALDA calculation for my system. But I am getting these two warnings given below with the yambo-5.1.2 version.

[xc] Functional : Perdew, Burke & Ernzerhof(X)+Perdew, Burke & Ernzerhof(C)
[xc] LIBXC used to calculate xc functional

[WARNING] USPP corrections to rho gradient not implemented

[WARNING] Fxc not coded for GGA. Using LDA part only of the functional

[WARNING] Fxc not coded for GGA. Using LDA part only of the functional

Does it mean that my results are not accurate/reliable if I perform ALDA on top of GGA? Here I have attached the report and input files. My ultimate goal is to analyze the peak transitions. But it is not possible with TDDFT-LRC in e-h space. Therefore, I had to do with ALDA. Does it mean that my options are limited? Thanks in advance
Niranji

Dear Niranji,
you can safely ignore the warning on USPP corrections, since your pseudo is not US, but NC.
This means that nothing is neglected in your case.
(The message should appear only when US pseudos are used, we did so in yambo-5.2, but it is just a change in the message)

For the GGA, my experience is that the corrections over the LDA part are minor.
If you want a full GGA kernel, you can try yambo 5.2 where Fxc is evaluated, buy default, via a numerical functional derivative of Vxc

However, from my experience, the convergence against the FxcGRLc is rather slow, and possibly the low cut-off would be source of most of the "error" in your simulations.

Best,
D.

Hi Davide,

Since I want to get to evaluate full GGA, I asked the admin to install the 5.2.0 version. But When I tried to run RPA calculation, it give me an error like this:
Here, I also attached the config.log file and the Report file .

Dear Niranji,

it seems that there are some problems in the compilation. You can try to not indicate netcdf/hdf5 path in the configure and let Yambo compile them and see if this solves the problem.

Best,
Daniele