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Queries about input and output files, running specific calculations, etc.


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apple
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Weights

#1 Post by apple » Mon Nov 15, 2010 12:38 am

hi all,
I am trying to run single k-point DOS calculations with the k-point files prepared manually. While running a simple job at the gamma point, I got the following error:
===============================
-----------------------------------------------------------------------------
| |
| W W AA RRRRR N N II N N GGGG !!! |
| W W A A R R NN N II NN N G G !!! |
| W W A A R R N N N II N N N G !!! |
| W WW W AAAAAA RRRRR N N N II N N N G GGG ! |
| WW WW A A R R N NN II N NN G G |
| W W A A R R N N II N N GGGG !!! |
| |
| Your generating k-point grid is not commensurate to the symmetry |
| of the lattice. This can cause slow convergence with respect |
| to k-points for HF type calculations |
| suggested SOLUTIONS: |
| ) if not already the case, use automatic k-point generation |
| ) shift your grid to Gamma (G) (e.g. required for hex or fcc lattice)
=========================================

I am confused about the message since I think I am actually using the gamma point as specified in my KPOINTS file (see below)

====================
Manual k-mesh generation
1
Reciprocal
0.0 0.0 0.0 1.
===================
What's the matter? Also, in the manual it says that in the KPOINT files generated manually, the sum of all weights for each kpoint must not be one. If I am interested in a single k-point (say gamma, or K, or others...one at a time though), do I just ignore the message and set the weights to 1 and later when looking at the DOS, sum the contributions up according to their respective weights for my geometry?
I appreciate your response.
Thanks.
Last edited by apple on Mon Nov 15, 2010 12:38 am, edited 1 time in total.

admin
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Weights

#2 Post by admin » Mon Dec 27, 2010 4:26 pm

1) I do not know which type of symmetry your cell has, but usually
you can choose the k-mesh manyally, and especially the Gamma point should be ok for any type of cell.
2)to calculate the DOS, the weights of the k-points have to sum up to 1, because otherwise the integrated DOS will not yield the number of electrons. If you want to generate the DOS by your own program from sets of single k-point data, the weights of the k-points have to be introduced in the routines doing the BZ-integration
Last edited by admin on Mon Dec 27, 2010 4:26 pm, edited 1 time in total.

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