[Pw_forum] Phonons at generic q-point

[Benedek, Nicole A]

Dear All,

I have been trying to run a parallel phonon calculation at generic q-point for a SrTiO3 multilayer (16 atoms) using espresso 4.0.3. I run an initial scf calculation with wf_collect=true and then a ph.x calculation with lnscf=true. The calculation always crashes with the following error (full input pasted below):

! ... rest of modes

     Representation    47      1 modes - To be done

     Representation    48      1 modes - To be done

     from openfilq : error #         1
     file sto_mag.wfc not found
     stopping ...

The wfc files are present and written to the same directory from which the calculation is running and this is not a 'recovered' calculation.

So far I have tried the following tests:

* The examples for Si at http://people.sissa.it/~degironc/QE-Tutorial/ (all run successfully);
* Phonon dispersion and q=0 calculations for bulk SrTiO3 (all run successfully);
* Phonon calculation at M for bulk SrTiO3, with lnscf=true (run successfully);
* Phonon calculation at q=0 for SrTiO3 multilayer (run successfully).

I also noticed the message 'Found additional translation' printed at the top of the output. I had a look through the source code (sgam_at.f90 and sgam_at_mag.f90), so I know this message is printed if the identity is found to have fractional translations. I found one previous post about this message in the archive (http://tinyurl.com/5k926j) but it seemed to concern how parallel jobs were re-started before the wf_collect keyword existed (I run all my calculations with wf_collect=true and my phonon calculation uses the same number of processors as the initial scf run). Is this message the source of my problems or is there something else going on? Any hints would be appreciated.

Cheers,

Nicole

Nicole Benedek
Research Associate
Department of Materials
Imperial College London

! INPUT FILE FOR PHONON CALC

Phonons of SrTiO3 multilayer at X
 &inputph
  tr2_ph=1.0d-14,
  amass(1)=87.62,
  amass(2)=47.88,
  amass(3)=15.9994,
  prefix='sto_mag',
  outdir='./'
  fildyn='sto_mag.dynX',
  lnscf=.true.
 /
 0.0 0.5 0.0 ! X point in BZ for orthorhombic primitive systems
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