[Pw_forum] ERROR about FFT grid: their fractional translations are incommensurate with FFT grid

Paolo Giannozzi p.giannozzi at gmail.com
Mon Jan 11 16:52:50 CET 2016


I do not get any fractional translation with the last QE version (it uses a
smarter, or less dumb, algorithm to find only valid fractional
translations). You may find 4 symmetry operations if you translate the
origin in the x direction. I do not think there are other symmetry
operations

Paolo

On Mon, Jan 11, 2016 at 3:48 PM, 한우현 <hanwooh at kaist.ac.kr> wrote:

> Hello!
>
>
>
> I'm trying to calculate band structures for boron monolayer.
>
>
>
> So I did scf calculation but there were some errors as below:
>
>
>
> 2 Sym. Ops. (no inversion) found
> (note: 6 additional sym.ops. were found but ignored
> their fractional translations are incommensurate with FFT grid)
>
> Since I want to get phonon dispersion curves for same structure, I can't
> use a 'use_all_frac' option and I think that I have to use 'nr1, nr2, nr3'
> options.
>
>
>
> Here is my question: How can I choose good nr1, nr2, nr3. that are
> commesurate with fractional translations.
>
>
> Thank you.
>
>
> * My input file is attatched
>
>
>
> ----------------------------------------------------------------------------------------
>
>
>
> &control
> calculation='scf',
> prefix='B',
> pseudo_dir = '../../pseudo/',
> outdir='./',
> tprnfor = .true.,
> tstress = .true.,
> /
> &system
> ibrav = 0, nat= 2, ntyp= 1,
> ecutwfc =60.0, ecutrho = 600,
> occupations='smearing', smearing='gaussian', degauss=0.01,
> /
> &electrons
> conv_thr = 1.0d-8
> mixing_beta= 0.7
>
> /
> CELL_PARAMETERS (angstrom)
> 1.61891208172746 0.00000000000000 0.00000000000000
> 0.00000000000000 2.87387342970566 0.00000000000000
> 0.00000000000000 0.00000000000000 10.00000000000000
> ATOMIC_SPECIES
> B 10.81 B.pbe-n-van_ak.UPF
> ATOMIC_POSITIONS (crystal)
> B 0.24494936440805 0.50000000000000 0.91277120106241
> B 0.74494902781767 0.00000000000000 0.00000000000000
> K_POINTS AUTOMATIC
> 24 24 1 0 0 0
>
>
>
>
>
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>



-- 
Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
Phone +39-0432-558216, fax +39-0432-558222
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