[Pw_forum] Phonon calculations - separating modes

[Sheena Shah]

Dear all,



Further to my previous email, here are some more details:



I have been running tests for phonon calculations by splitting up the modes for each q-point using start_irr and last_irr input parameters (an example of the input file used for the Gamma-point is given below).  I was able to obtain the correct frequencies at each q-point by collecting all data-file.xml.#iq.#irr files in one directory and running ph.x one last time.



As a final step I was planning to run an electron-phonon calculation. The problem I encountered was that at the end of a phonon calculation performed as described above I do not have a correct deformation potential file (a different *.dv1 file is obtained depending on the start_irr and last_irr parameters). I noticed that for the calculation where last_irr is equal to the last irreducible representation the *.dv1 file has the same size as the one from a calculation performed over all representations at once. However, the electron-phonon parameters obtained using these two files are very different. Is there a way I could recover the correct deformation potential at the end of an irreducible-split phonon calculation?



&inputph

  tr2_ph=1.0d-14,

  prefix='c',

  fildvscf='dv',

  amass(1)=12.011,

  outdir='./',

  fildyn='c.dyn',

  trans=.true.,

  lnscf=.true.,

  strart_irr=1,

  last_irr=3

 /

 0.000000000 0.000000000 0.000000000



Thank you for your help.



Sheena Shah

sheena.shah at materials.ox.ac.uk<mailto:Sheena.shah at materials.ox.ac.uk>

University of Oxford

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