[Pw_forum] q2r.x on rhomboheral

[Stefano de Gironcoli]

Adeagbo Waheed Adeniyi wrote:

> Thank you  Dr Stefano,
> It is the first time I encounter the error when I execute q2r.x in
> particular for Rhombohedral structure which I am doing for the first
> time.
> I didn't have any problem with other systems (cubic/fcc) I have 
> calculated so far.
>
> Whenever I supplied any value for celldim(3) for Rhombohedral (ibrav=5) 

I guess the problem is that ibrav=5 requires the value of celldm(4) and 
not celldm(3)
moreover the supplied value should be the same as the one used in the 
scf calculation.

stefano


>
> I always get the following when I execute kpoint.x for 2x2x2, 
> ========================
>     4
>     1   0.0000000  0.0000000  0.0000000   1.00
>     2   0.3535534 -0.2041241  0.2886751   3.00
>     3   0.3535534  0.2041241  0.5773503   3.00
>     4   0.0000000  0.0000000  0.8660254   1.00
> ===========================================
> These are the set of values I used as q-vectors in the calculation of
> phonons.
> May be my input file is wrong. I have no idea
> ===============
> &CONTROL
>                  calculation = 'phonon' ,
>                 restart_mode = 'from_scratch' ,
>                       outdir = 'tmp/' ,
>                   pseudo_dir = '/home4/hes11/hes110/espresso/pseudo/'
> ,
>                       prefix = 'bi' ,
>                      tstress = .true. ,
>                      tprnfor = .true. ,
>  /
>  &SYSTEM
>                        ibrav = 5,
>                       celldm(1) = 8.9263,celldm(4)=0.53954
>                          nat = 2,
>                         ntyp = 1,
>                      ecutwfc = 80.0 ,
>                      ecutrho = 360.0 ,
>                      occupations='smearing'
>                      degauss = 0.02,
>                      smearing = 'fermi-dirac'
>                      nspin = 1,
>                      starting_magnetization(1) = 0.0
>  /
>  &ELECTRONS
>             electron_maxstep = 60,
>                     conv_thr = 1.0D-7 ,
>                  startingpot = 'atomic' ,
>                  startingwfc = 'random' ,
>                  mixing_mode = 'plain' ,
>              diagonalization = 'david' ,
> /
>  &phonon
>     xqq(1) = 0.3535534, xqq(2) =-0.2041241, xqq(3) =0.2886751
> /
> ATOMIC_SPECIES
>    Bi  208.98038 Bi.pbe_nc.UPF
> ATOMIC_POSITIONS crystal
> Bi       0.249929420   0.249929420   0.249929420
> Bi       0.750070580   0.750070580   0.750070580
> K_POINTS automatic
>   16 16 16      1 1 1
> ================================================================
>