[QE-users] phonon frequencies at Gamma using qplot = .true. along K-Gamma-L

[Pietro Davide Delugas]

Thanks for reporting
this is a bug, I started an issue on the GitLab repository. If you are 
interested you may follow the discussion here.
<https://gitlab.com/QEF/q-e/issues/129>
Thanks again
Pietro


On 6/23/19 8:55 PM, Hari Paudyal wrote:
> Dear experts,
>
> To calculate the phonon along a specific path of BZ (K-Gamma-L) for 
> Si, I used  qplot = .true. and q_in_band_form = .true.  (taking 2 
> points in between).  Surprisingly, I got the following frequencies at 
> Gamma,
>      q = (    0.000000000   0.000000000   0.000000000 )
>
>  **************************************************************************
>      freq (    1) =      11.535533 [THz] =     384.783979 [cm-1]
>      freq (    2) =      11.535533 [THz] =     384.783979 [cm-1]
>      freq (    3) =      11.535533 [THz] =     384.783979 [cm-1]
>      freq (    4) =      18.554595 [THz] =     618.914662 [cm-1]
>      freq (    5) =      18.554595 [THz] =     618.914662 [cm-1]
>      freq (    6) =      18.554595 [THz] =     618.914662 [cm-1]
>  **************************************************************************
>
> On the other hand, If I calculate only at Gamma point, I get
>      q = (    0.000000000   0.000000000   0.000000000 )
>
>  **************************************************************************
>      freq (    1) =      -0.117104 [THz] =      -3.906180 [cm-1]
>      freq (    2) =      -0.117104 [THz] =      -3.906180 [cm-1]
>      freq (    3) =      -0.117104 [THz] =      -3.906180 [cm-1]
>      freq (    4) =      15.035771 [THz] =     501.539319 [cm-1]
>      freq (    5) =      15.035771 [THz] =     501.539319 [cm-1]
>      freq (    6) =      15.035771 [THz] =     501.539319 [cm-1]
>  **************************************************************************
>
> Why am I getting the large frequencies at Gamma if I calculate along 
> K-Gamma-L? Do I need to specify Gamma always in the first?Why?
>
> My input files for the scf and phonon for Si are as the following.
>
>  &control
>     calculation     = 'scf'
>     prefix          = 'Si'
>     restart_mode    = 'from_scratch'
>     wf_collect      = .true.
>     pseudo_dir      = './'
>     outdir          = './'
>  /
>  &system
>     ibrav           = 2
>     celldm(1)       = 10.261217
>     nat             = 2
>     ntyp            = 1
>     ecutwfc         = 45.0
>  /
>  &electrons
>     diagonalization = 'david'
>     mixing_beta     = 0.3
>     conv_thr        = 1.0d-10
> /
> ATOMIC_SPECIES
>   Si  28.0855  Si.pz-vbc.UPF
> ATOMIC_POSITIONS alat
>   Si  0.00  0.00  0.00
>   Si  0.25  0.25  0.25
> K_POINTS automatic
> 8 8 8 0 0 0
>
> Si
> &inputph
>  outdir    = './',
>  prefix    = 'Si',
>  fildyn    = 'Si.dyn',
>  fildvscf  = 'dvscf',
>  ldisp     = .true.,
>  tr2_ph    = 1.0d-14
>  qplot     = .true.
>  q_in_band_form = .true.
> /
> 3
> -0.7500000   0.7500000   0.0000000   2   ! K
>  0.0000000   0.0000000   0.0000000   2   ! G
> -0.5000000   0.5000000   0.5000000   1   ! L
>
> Thank You,
> Hari Paudyal
> SUNY Binghamton
>
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20190624/8d6dbf32/attachment.html>