Dear Huang,
--- On Fri, 12/18/09, Zhen Huang <huang87 at purdue.edu> wrote:
> However, I found the software failed to give some of the
> force constant.
> 1 1
> 252.12788999 0.00000000 -0.00114015 0.00000000
> -14.77300805 0.00000000
> -0.00114015 0.00000000 ************ 0.00000000
> -0.06520954 0.00000000
>
The software, fortunately, did not fail, it just stated that something wrong in
your input files which resulted in large IFC components that can not be printed
using the f12.8 format.
Reasons for this:
1.
> ??? ecutwfc =16.0,
> ??? degauss=0.05
ecutwfc looks very small, I would use 25Ry.
degauss is quite large, usually it is around 0.02
You did not specify ecutrho (8-12 times of ecutwfc) which is important for
ultrasoft PsPs (see your PsP below).
> ?C? 12.0107? C.pz-rrkjus.UPF
2.
> ATOMIC_POSITIONS
> ?C 0.462? 0.5? 0.000
> ?C 0.538? 0.5? 0.000
> ?C 0.462? 0.5? 0.333
> ?C 0.538? 0.5? 0.333
> ?C 0.500? 0.5? 0.500
> ?C 0.577? 0.5? 0.500
> ?C 0.500? 0.5? 0.833
> ?C 0.577? 0.5? 0.833
You have mistaken here as you left an important parameter. By default atomic
positions are in units of the lattice parameter "a". If you visualize your
structure you will find very funny picture.
In fact, atomic positions provided are in units of basis vectors, i.e. you
should add "crystal" after "ATOMIC_POSITIONS"
I think this is the main reason.
3.
> ? tr2_ph=1.0d-12,
Try -14.
Bests,
Eyvaz.
-------------------------------------------------------------------
Prof. Eyvaz Isaev,
Theoretical Physics Department, Moscow State Institute of Steel & Alloys,
Russia,
Department of Physics, Chemistry, and Biology (IFM), Linkoping University,
Sweden
Condensed Matter Theory Group, Uppsala University, Sweden
Eyvaz.Isaev at fysik.uu.se, isaev at ifm.liu.se, eyvaz_isaev at yahoo.com
