[Pw_forum] zigzag nanotube input error

[Hande Ustunel]

Hi,

If you really have the balnk line between the first and the second atomic
coordinates that could be your problem. A more severe problem is that the
code failed to read the configuration you meant to restart from. This could
be due to the space in the name of your outdir, again of course if you
really have it there in your input.

As for the parameters, first off, there's a single k point should be enough
in the plane perp to the NT axis. To determine the no of kpoints along the
axis, you should do a convergence study, increasing the number until you
are satisfied with the difference of energy values (or whichever value you
are interested in). Same goes for Ecut. You are lucky in that a (5,0) has a
substantial gap so you don't have to worry about smearing. Your vacuum
value seems a little small to me. I usually leave about 10 A between the
closest atoms belonging to neigboring images. But then again you should
increase this value a little bit and see if it has any effects. These are
all the parameters I can think of.

Best wishes,
Hande Ustunel

On Tue, 27 Nov 2007, meisam aghtar wrote:

> hi
> I had a problem during runing the pw input of  (5,0) nanotube . the input and the error is in following. another problem is that I dont know wich parameters should be in a pw input for a nanotube.
> &CONTROL
>                  calculation = 'scf' ,
>                 restart_mode = 'restart',
>                       outdir = '/home/meisam/projhe/5-0/band/ scratch/'
>                   pseudo_dir = '/home/meisam/espresso-3.1.1/pseudo/',
>                       prefix = 'cnt-scf' ,
>  /
>  &SYSTEM
>                        ibrav = 4,
>                    celldm(1) = 19,
>                    celldm(3) = 0.282460,
>                          nat = 20,
>                         ntyp = 1,
>                      ecutwfc = 30,
>  /
>  
> &ELECTRONS
>  /
> ATOMIC_SPECIES
>     C   12.00000  C.pz-vbc.UPF
> ATOMIC_POSITIONS alat
>     C      0.194660000    0.000000000    0.000000000
>     
>     C      0.157490000    0.114420000    0.070620000
>     C      0.060150000    0.185130000    0.000000000
>     C     -0.060150000    0.185130000    0.070620000
>     C     -0.157490000    0.114420000    0.000000000
>     C     -0.194660000    0.000000000    0.070620000
>     C     -0.157490000   -0.114420000    0.000000000
>     C     -0.060150000   -0.185130000    0.070620000
>     C      0.060150000   -0.185130000    0.000000000
>     C      0.157490000   -0.114420000    0.070620000
>     C      0.157490000    0.114420000    0.211850000
>     C      0.060150000    0.185130000    0.282460000
>     C     -0.060150000    0.185130000    0.211850000
>     C     -0.157490000    0.114420000    0.282460000
>     C     -0.194660000    0.000000000    0.211850000
>     C     -0.157490000   -0.114420000    0.282460000
>     C     -0.060150000   -0.185130000    0.211850000
>     C      0.060150000   -0.185130000    0.282460000
>     C      0.157490000   -0.114420000    0.211850000
>     C      0.194660000    0.000000000    0.282460000
> K_POINTS automatic
>   2 2 14   1 1 1
>  erro :
>     Starting configuration read from file     cnt-scf.save
>      Failed to open file 
>     cnt-scf.save
>      Using input configuration
> 
>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>      from setup : error #         1
>      Wrong atomic coordinates
>  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>      stopping ...
> 
> 
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-- 
Hande Ustunel
Department of Physics
Office 439
Middle East Technical University
Ankara 06531, Turkey
Tel : +90 312 210 3264
http://www.physics.metu.edu.tr/~hande