[QE-users] High-symmetry path in bands.x differs from K_POINTS input

[Vahid Askarpour]

Not sure who Vishad is but the coordinates in your input file is in crystal. The coordinates in bands.x output is in cartesian.

Cheers,
Vahid

> On Sep 28, 2025, at 10:18 AM, wenusaras <wenusaras at uom.lk> wrote:
> 
> CAUTION: The Sender of this email is not from within Dalhousie.
> 
> Dear Vishad,
> 
> Thank you very much for your quick reply.
> Could you please provide a bit more detail on what you meant by “One is
> crystal, the other is cartesian”?
> Let me restate my situation for clarity.
> 
> In my band-structure input (pw.scf.bands.in, calculation = 'bands') for
> a 2-D material with ibrav = 8, I specify the k-path in crystal
> coordinates:
> 
> K_POINTS crystal_b
> 5
> 0.00  0.00  0.00 10 !G
> 0.50  0.00  0.00 10 !X
> 0.50  0.50  0.00 10 !C
> 0.00  0.50  0.00 10 !Y
> 0.00  0.00  0.00 10 !G
> 
> After running this SCF/bands calculation and then bands.x with
> &bands
>   prefix  = 'A'
>   filband = 'B.dat'
>   lsym = .false.
> /
> 
> the bands.x output lists:
>    high-symmetry point:  0.0000 0.0000 0.0000   x coordinate   0.0000
> --> G
>    high-symmetry point:  0.5000 0.0000 0.0000   x coordinate   0.5000
> --> X
>    high-symmetry point:  0.5000 1.7459 0.0000   x coordinate   2.2459
> --> Not C
>    high-symmetry point:  0.0000 1.7459 0.0000   x coordinate   2.7459
> --> Not Y
>    high-symmetry point:  0.0000 0.0000 0.0000   x coordinate   4.4918
> --> G
> 
> I was expecting the same crystal coordinates as in the input, but
> bands.x reports larger y-values such as 1.7459.(attached bands.x output)
> Could you please advise me on how to get the output high-symmetry points
> to match the crystal coordinates I set in the input (pw.scf.bands.in)?
> 
> (I also notice that for simpler cells (e.g. ibrav = 1) the reported
> points match the input fractions—perhaps the cell vectors)
> 
> Thank you again for your help.
> Wenusara Satheekshana
> 
> 
> ______________________________________________________________________________________________________________________________________
> On 2025-09-28 17:33, Vahid Askarpour wrote:
>> One is crystal, the other is cartesian.
>> 
>> Cheers,
>> Vahid
>> 
>> Vahid Askarpour
>> Department of Physics and Atmospheric Science
>> Dalhousie University
>> Halifax, Canada
>> 
>>> On Sep 28, 2025, at 8:49 AM, wenusaras <wenusaras at uom.lk> wrote:
>>> 
>>> CAUTION: The Sender of this email is not from within Dalhousie.
>>> 
>>> Dear QE users,
>>> 
>>> I am new to Quantum ESPRESSO and working on a 2D material (ibrav = 8)
>>> using QE v7.2.
>>> For a band-structure calculation I provided the following path in the
>>> pw.scf bands input:
>>> 
>>> K_POINTS crystal_b
>>> 5
>>> 0.00  0.00  0.00 10
>>> 0.50  0.00  0.00 10
>>> 0.50  0.50  0.00 10
>>> 0.00  0.50  0.00 10
>>> 0.00  0.00  0.00 10
>>> 
>>> The SCF run completed, and I then executed bands.x.
>>> However, the bands.x output lists different high-symmetry points:
>>> 
>>>  Reading collected, re-writing distributed wavefunctions
>>>    high-symmetry point:  0.0000 0.0000 0.0000   x coordinate   0.0000
>>>    high-symmetry point:  0.5000 0.0000 0.0000   x coordinate   0.5000
>>>    high-symmetry point:  0.5000 1.7459 0.0000   x coordinate   2.2459
>>>    high-symmetry point:  0.0000 1.7459 0.0000   x coordinate   2.7459
>>>    high-symmetry point:  0.0000 0.0000 0.0000   x coordinate   4.4918
>>> 
>>> My goal is to obtain the band structure along exactly the k-path
>>> specified in the input file, but the output shows different
>>> coordinates
>>> (e.g., 1.7459 instead of 0.5).
>>> 
>>> Could someone clarify why bands.x is changing the path and how I can
>>> ensure the high symmetry points match with the input?
>>> 
>>> Thank You in advance
>>> Wenusara Satheekshana
>>> _______________________________________________________________________________
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>>> users mailing list users at lists.quantum-espresso.org
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>> 
>> _______________________________________________________________________________
>> The Quantum ESPRESSO Foundation stands in solidarity with all
>> civilians worldwide who are victims of terrorism, military aggression,
>> and indiscriminate warfare.
>> --------------------------------------------------------------------------------
>> Quantum ESPRESSO is supported by MaX (www.max-centre.eu)
>> users mailing list users at lists.quantum-espresso.org
>> https://lists.quantum-espresso.org/mailman/listinfo/users
> 
> --
> Thank You
> Wenusara Satheekshana
> <bands.gnr.out>