q-point weight

[JohannesMeusburger]

Good morning,

First of all many thanks for developing this fantastic code. I am using Quantum Espresso to calculate the phonons and was just wondering how I can obtain the weight values for each of the q-points.

All the best and many thanks,

Johannes

[singularitti]

Hi @JohannesMeusburger, thank you for using our code!
The reciprocal spaces of phonons and electrons are the same, so if you have the weights of the k-points from electron structure calculations, you can use them directly in your phonon calculations.
Since you are using QE to do phonon calculations, they use the Monkhorst-Pack grid also, as in electron structure calculations. For example, if you have nq1 = 4, nq2 = 4, nq3 = 4 in the phonon input, you can set the K_POINTS card to automatic and mesh to be 4 4 4 in the PWscf input. Run for a few seconds and stop, and read the following wk values in the output (Set verbosity = 'high' to see this):

     number of k points=    28
                       cart. coord. in units 2pi/alat
        k(    1) = (  -0.0833333   0.0833333   0.0833333), wk =   0.0185185
        k(    2) = (  -0.2500000   0.2500000  -0.0833333), wk =   0.0555556
        k(    3) = (  -0.4166667   0.4166667  -0.2500000), wk =   0.0555556
        k(    4) = (   0.4166667  -0.4166667   0.5833333), wk =   0.0555556
        k(    5) = (   0.2500000  -0.2500000   0.4166667), wk =   0.0555556
        k(    6) = (   0.0833333  -0.0833333   0.2500000), wk =   0.0555556
        k(    7) = (  -0.0833333   0.4166667   0.0833333), wk =   0.0555556
        k(    8) = (  -0.2500000   0.5833333  -0.0833333), wk =   0.1111111
        k(    9) = (   0.5833333  -0.2500000   0.7500000), wk =   0.1111111
        k(   10) = (   0.4166667  -0.0833333   0.5833333), wk =   0.1111111
        k(   11) = (   0.2500000   0.0833333   0.4166667), wk =   0.1111111
        k(   12) = (  -0.0833333   0.7500000   0.0833333), wk =   0.0555556
        k(   13) = (   0.7500000  -0.0833333   0.9166667), wk =   0.1111111
        k(   14) = (   0.5833333   0.0833333   0.7500000), wk =   0.1111111
        k(   15) = (   0.4166667   0.2500000   0.5833333), wk =   0.1111111
        k(   16) = (  -0.0833333  -0.9166667   0.0833333), wk =   0.0555556
        k(   17) = (  -0.2500000  -0.7500000  -0.0833333), wk =   0.1111111
        k(   18) = (  -0.0833333  -0.5833333   0.0833333), wk =   0.0555556
        k(   19) = (  -0.2500000   0.2500000   0.2500000), wk =   0.0185185
        k(   20) = (  -0.4166667   0.4166667   0.0833333), wk =   0.0555556
        k(   21) = (   0.4166667  -0.4166667   0.9166667), wk =   0.0555556
        k(   22) = (   0.2500000  -0.2500000   0.7500000), wk =   0.0555556
        k(   23) = (  -0.2500000   0.5833333   0.2500000), wk =   0.0555556
        k(   24) = (   0.5833333  -0.2500000   1.0833333), wk =   0.1111111
        k(   25) = (   0.4166667  -0.0833333   0.9166667), wk =   0.1111111
        k(   26) = (  -0.2500000  -1.0833333   0.2500000), wk =   0.0555556
        k(   27) = (  -0.4166667   0.4166667   0.4166667), wk =   0.0185185
        k(   28) = (   0.4166667  -0.4166667   1.2500000), wk =   0.0555556

                       cryst. coord.
        k(    1) = (   0.0833333   0.0833333   0.0833333), wk =   0.0185185
        k(    2) = (   0.0833333   0.0833333   0.2500000), wk =   0.0555556
        k(    3) = (   0.0833333   0.0833333   0.4166667), wk =   0.0555556
        k(    4) = (   0.0833333   0.0833333  -0.4166667), wk =   0.0555556
        k(    5) = (   0.0833333   0.0833333  -0.2500000), wk =   0.0555556
        k(    6) = (   0.0833333   0.0833333  -0.0833333), wk =   0.0555556
        k(    7) = (   0.0833333   0.2500000   0.2500000), wk =   0.0555556
        k(    8) = (   0.0833333   0.2500000   0.4166667), wk =   0.1111111
        k(    9) = (   0.0833333   0.2500000  -0.4166667), wk =   0.1111111
        k(   10) = (   0.0833333   0.2500000  -0.2500000), wk =   0.1111111
        k(   11) = (   0.0833333   0.2500000  -0.0833333), wk =   0.1111111
        k(   12) = (   0.0833333   0.4166667   0.4166667), wk =   0.0555556
        k(   13) = (   0.0833333   0.4166667  -0.4166667), wk =   0.1111111
        k(   14) = (   0.0833333   0.4166667  -0.2500000), wk =   0.1111111
        k(   15) = (   0.0833333   0.4166667  -0.0833333), wk =   0.1111111
        k(   16) = (   0.0833333  -0.4166667  -0.4166667), wk =   0.0555556
        k(   17) = (   0.0833333  -0.4166667  -0.2500000), wk =   0.1111111
        k(   18) = (   0.0833333  -0.2500000  -0.2500000), wk =   0.0555556
        k(   19) = (   0.2500000   0.2500000   0.2500000), wk =   0.0185185
        k(   20) = (   0.2500000   0.2500000   0.4166667), wk =   0.0555556
        k(   21) = (   0.2500000   0.2500000  -0.4166667), wk =   0.0555556
        k(   22) = (   0.2500000   0.2500000  -0.2500000), wk =   0.0555556
        k(   23) = (   0.2500000   0.4166667   0.4166667), wk =   0.0555556
        k(   24) = (   0.2500000   0.4166667  -0.4166667), wk =   0.1111111
        k(   25) = (   0.2500000   0.4166667  -0.2500000), wk =   0.1111111
        k(   26) = (   0.2500000  -0.4166667  -0.4166667), wk =   0.0555556
        k(   27) = (   0.4166667   0.4166667   0.4166667), wk =   0.0185185
        k(   28) = (   0.4166667   0.4166667  -0.4166667), wk =   0.0555556

[singularitti]

Is your question solved? @JohannesMeusburger

[JohannesMeusburger]

Hi Ryan, Thanks so much for your help and I am sorry I totally forgot to reply. Setting the verbosity to high worked out perfectly. Thanks again for your help and also the detailed explanation! Have a good day, Johannes

…

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