[Pw_forum] big differences in relativistic phonon calculations between v5.0 and v5.3

[Alaska Subedi]

Things work again in the svn version.

Sorry for the noise.

Alaska

On Sun, Apr 7, 2013 at 2:45 AM, Alaska Subedi <asubedi at gmail.com> wrote:
> Dear all,
>
> When I calculate the phonon dispersions of PbTe using the relativistic
> pseudopotentials from pslibrary, I find that v5.0 gives stable phonon
> dispersions while v5.3 (and v5.2 as well) gives unstable phonons along
> q = (0, x, 0). There is also a published work
> http://prb.aps.org/abstract/PRB/v85/i18/e184303 with stable PbTe
> phonons using relativistic pseudopotentials of pslibrary. However, I
> cannot get stable phonon frequencies anymore with the new version of
> the code with the sets of relativistic pseudopotentials that I tried:
> lda and gga ultrasoft and normconserving.
>
> Could anyone please check what has gone wrong in newer versions?
>
> The input files are below.
>
> PbTe.scf.in:
>
> &control
>     calculation = 'scf'
>     restart_mode = 'from_scratch',
>     tprnfor = .true.
>     tstress = .true.
>     prefix = 'PT-ph2',
>     pseudo_dir = './pseudo/'
>     outdir = './tmp/'
> /
>
> &system
>     ibrav = 2
>     celldm(1) = 12.056453 ! 6.38 angstroms
>     nat = 2
>     ntyp = 2
>     ecutwfc = 50
>     ecutrho = 500
>     occupations = 'fixed'
>     lspinorb = .true.
>     noncolin = .true.
> /
>
> &electrons
>     conv_thr = 1.0d-12
> !    diagonalization = 'cg'
> !    mixing_mode = 'local-TF' ! 'plain'
>     mixing_beta = 0.2d0
> /
>
> ATOMIC_SPECIES
>  Pb  207.21      Pb.rel-pz-dn-rrkjus_psl.0.2.2.UPF
>  Te  127.60      Te.rel-pz-dn-rrkjus_psl.0.2.2.UPF
> ATOMIC_POSITIONS crystal
> Pb       0.500   0.500  0.500
> Te       0.000   0.000  0.000
> K_POINTS automatic
>   8  8  8  0  0  0
>
>
> PbTe.ph.in:
>
> &inputph
>   tr2_ph=1.0d-18,
>   prefix='PT-ph2',
>   alpha_mix(1)=0.2,
>   nmix_ph=5,
>   amass(1) = 207.21
>   amass(2) = 127.60
>   outdir='./tmp/',
>   fildyn='PT-ph0.dyn2'
> /
>    0.000000000000000E+00   0.5000000000000E+00   0.000000000000000E+00