[Pw_forum] different structure under xyz file and scf file for carbon nanotube

[chengyu yang]

Hi everyone,
     I have a question. When I put my atom positions unde .xyz file, and
input into xcrysden, they will generate a round carbon nanotube . However,
when I put the same atomic positions under scf.in file, and then input them
into xcrysden, I got departed four parts like four quarters of a nanotube,
all outwards. I feel very stange about this. Can anyone tell me is there
anything wrong with the scf file? I want a round carbon nanotube because it
is more vivid and instinctive.
   my input files are like this:

    &CONTROL
                 calculation = 'scf' ,
                restart_mode = 'from_scratch' ,
                      outdir = '/home/mems/espresso-4.2/tmp/' ,
                  pseudo_dir = '/home/mems/espresso-4.2/pseudo/' ,
                      prefix = 'cnt' ,
 /
 &SYSTEM
                       ibrav = 6,
                   celldm(1) = 21.764541128,celldm(3)=0.213765379
                         nat = 24,
                        ntyp = 1,
                     ecutwfc = 75 ,
 /
 &ELECTRONS
                    conv_thr = 1.0d-8 ,
                 mixing_beta = 0.7 ,
 /
ATOMIC_SPECIES
    C   12.01100  C.pz-vbc.UPF
ATOMIC_POSITIONS angstrom
  C        4.085165     -0.000000   -1.231010
  C        3.838021     1.399343    -1.231010
  C        3.537856     2.042582     0.000000
  C        2.624152     3.130877     0.000000
  C        2.042582     3.537856    -1.231010
  C        0.707144     4.023496    -1.231010
  C        0.000000     4.085165     0.000000
  C       -1.399343     3.838021     0.000000
  C       -2.042582     3.537856    -1.231010
  C       -3.130877     2.624152    -1.231010
  C       -3.537856     2.042582     0.000000
  C       -4.023496     0.707144     0.000000
  C       -4.085165     0.000000    -1.231010
  C       -3.838021    -1.399343    -1.231010
  C       -3.537856    -2.042582     0.000000
  C       -2.624152    -3.130877     0.000000
  C       -2.042582    -3.537856    -1.231010
  C       -0.707144    -4.023496    -1.231010
  C       -0.000000    -4.085165     0.000000
  C        1.399343    -3.838021     0.000000
  C        2.042582    -3.537856    -1.231010
  C        3.130877    -2.624152    -1.231010
  C        3.537856    -2.042582     0.000000
  C        4.023496    -0.707144     0.000000

K_POINTS automatic
  4 4 4   1 1 1

and my .xyz file are like
24
(6,6) Nanotube -- TubeGen 3.3, J T Frey, University of Delaware
  C        4.085165    -0.000000    -1.231010
  C        3.838021     1.399343    -1.231010
  C        3.537856     2.042582     0.000000
  C        2.624152     3.130877     0.000000
  C        2.042582     3.537856    -1.231010
  C        0.707144     4.023496    -1.231010
  C        0.000000     4.085165     0.000000
  C       -1.399343     3.838021     0.000000
  C       -2.042582     3.537856    -1.231010
  C       -3.130877     2.624152    -1.231010
  C       -3.537856     2.042582     0.000000
  C       -4.023496     0.707144     0.000000
  C       -4.085165     0.000000    -1.231010
  C       -3.838021    -1.399343    -1.231010
  C       -3.537856    -2.042582     0.000000
  C       -2.624152    -3.130877     0.000000
  C       -2.042582    -3.537856    -1.231010
  C       -0.707144    -4.023496    -1.231010
  C       -0.000000    -4.085165     0.000000
  C        1.399343    -3.838021     0.000000
  C        2.042582    -3.537856    -1.231010
  C        3.130877    -2.624152    -1.231010
  C        3.537856    -2.042582     0.000000
  C        4.023496    -0.707144     0.000000

-------
Chengyu Yang
Graduate student
Material Science and Engineering.
U of Central Florida

Chengyu.young at gmail.com
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