Yambo Community Forum

Unfortunately not, as usually they are not needed, it is not a calculation done by yambo, as they are exported from QE.
Here in attachment a script to extract the dipoles, you need to adapt for the reading of the wfs.

Best,
Daniele

I see, thank you!

Dear Daniele,

I think the ordering in 'ns.wf_fragments_*' files should be
from left nband, spin, gvector, Re/Im(wf_coefficients),
right?

The number of g_vec obtained from './setup/G_shells_finder.F' are much larger than the above wave function coefficients.
Actually, the number of wave function coefficients are the same with the 'Max WF components' and the number of 'g_vec' is the same with 'RL vectors (CHARGE)'.

<---> Max WF components : 9843
<---> RL vectors (WF): 9843
<---> RL vectors (CHARGE): 79117

So how do we match 'g_vec' and wave function coefficients?

Best

Dear Fadil,

I think the ordering in 'ns.wf_fragments_*' files should be
from left nband, spin, gvector, Re/Im(wf_coefficients),
right?

Yes sorry, I wrote from left instead then from right.

G_vec contains all the gvectors which are the ones of the charge, i.e. (G-G') where G are the ones of the wfs (wf_ng along the code).
About the matching, I would not want to send you on the wrong path. In the code the procedure to go from G to R space is alway done via FFT, someone else more expert in the ordering can give you more precise details.

Best,
Daniele

Dear Fadil,

concerning your question about the matching of vectors in g_vec (density) with FFT grids and wave functions, you may want to have a look at the yambo-internal map:

ir=fft_g_table(ig,iGo)

which, given a G-vector index ig, maps it to the FFT grid. (Actually, it is G-Go which is mapped).

Coming to the connection of wfcs and rho G-vectors:
assuming wfc contains components up to G*, the charge density contains component up to 2G*, making the ecutrho value 4 times that of the wave functions.
As a rule of thumb, the G-vecotrs for wfcs are about 1/8 of those of the density (both are distributed in spheres, one with radius 1/2 of the other one).

HTH

Andrea

Dear Daniele and Andrea,

Thank you for your help!

G_vec contains all the gvectors which are the ones of the charge, i.e. (G-G') where G are the ones of the wfs (wf_ng along the code).

Where can I find the 'wf_ng' ?
It is not in the './setup/G_shells_finder.F'.

Best

Dear Fadil,

wf_ng is assigned by the p2y interface and stored in the ns.db1 database.

you can find it here:
/interfaces/p2y/p2y_db1.F

it can be changed by setting in input the FFTGvecs variable (see ./src/interface/INIT_load.F)

Best,

Daniele

Dear Daniele,

The q=0 max strength is correct, while for finite q the pre-factor is wrong.
Note the values reported are normalised to the maximum value so the relative intensity for each q is correct.
The absolute value instead should be modified as S=S*10^-10/|q|^2

Is the above prefactor correct for q=/0 polarizabilities (\alpha)?
-q=0 seems correct but the polarizabilities for q=/0 are very high with versions 5.0.3 and 5.0.4.

Dear Fadil,

yes, the prefactor now is correct.


Best,
Daniele

It seems no.
Can you please check the attached outputs? It is the same with the 5.0.4.
Since I apply the Coulomb Cutoff, I need to rescale the results.
Is it \alpha=\alpha*10^-10/|q|^2 ?