phonon + electric field is not implemented.
From the phonon.f90 file:

  ! Not implemented in ph.x:
  ! [6] [5] + constraints on the magnetization
  ! [7] [6] + Hubbard U
  ! [8] [7] + Hybrid functionals
  ! [9] ? + External Electric field
  ! [10] ? + nonperiodic boundary conditions.

HTH,

Andrea

On Tue, 2014-10-14 at 16:56 +0800, 秦新明 wrote:
> Dear all
>   I got a serious problem when using QE to apply dipole corrections in the 
> phonon calculation for a slab with a large dipole moment. I perform the 
> phonon calculations with and without the dipole correction. And I find that 
> the corresponding phonons are very different. When the dipole correction is 
> applied, two acoustic branches are imaginary at high frequencies. However, 
> without the dipole correction, all frequencies are positive and the phonon 
> dispersion is similar with the reslut form the frezon-phonon calculction.  
> Can the dipole correction be neglected ?
>   Furthermore, both pw.x and ph.x do not support the symmetry when appling 
> the dipole correction. Then a large number of k or q points are required in 
> practical calculations. Can ph.x calcuclate phonons well with the dipole 
> correction ?
>   I'm thirsty for your reply. Thanks!
>  
>   Best regards
> 
>   Xinming
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-- 
Andrea Dal Corso                    Tel. 0039-040-3787428
SISSA, Via Bonomea 265              Fax. 0039-040-3787249
I-34136 Trieste (Italy)             e-mail: [email protected]


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