[Pw_forum] vc-relax (one dimension supercell)

[REI.BOND]

Dear all,

(sorry! Since pre- mail has been garbled, it is sent once again. )

I have a problem.

My problem of the 16 atom supercell system ( one-dimension system ), I
am trying to vc-relax.

First, when it calculates in a supercell, is it amusing that pressure
is applied from a vacuum layer? (in my calculation, vacuums layer is x
and y)

Then, if  cell_dofree = 'xyz' is used, a vacuum layer will become small
rapidly.

Does my calculation have any problems?


Thanks,

REI

---input----

 &control
    calculation='vc-relax'
!    restart_mode='restart',
    tprnfor = .true.
    tstress = .true.
    prefix='110',
    pseudo_dir = './',
    outdir='./'
    forc_conv_thr = 1.d-6
    etot_conv_thr = 1.d-7,
    nstep =100000
 /
 &system
    ibrav=6,
    celldm(1) = 40.50311907 ,
    celldm(3) = 0.180919129 ,
!    celldm(3) = 4.362274784 ,
    nat=  14,
    ntyp= 2,
    ecutwfc =80.0,
 /
 &electrons
    diagonalization = 'cg'
    electron_maxstep = 100
    conv_thr =  1.0d-12,
    mixing_beta = 0.2,
 /
 &ions
    bfgs_ndim = 3,
 /
 &cell
  cell_dofree = 'xyz' ,
  press_conv_thr=0.1
 /
ATOMIC_SPECIES
   Si 28.086     Si.pz-vbc.UPF
   H 1.00782503207 H.pz-vbc.UPF
ATOMIC_POSITIONS bohr
Si       6.680764370   8.898916109   5.986070989
Si       9.029846753   5.231537887   5.363083201
Si       6.680057629   1.564614309   5.986065052
Si       4.221207325   8.899147367   2.313388654
Si       1.871413129   5.232223481   2.936367832
Si       4.220504860   1.564853884   2.313381924
H        8.432421873  11.126743390   6.027800731
H        2.468854211  -0.662974560   2.271647941
H        2.469974729  11.127305994   2.271650709
H        8.431281864  -0.663551556   6.027799087
H       -0.711612701   5.232463267   1.803772875
H        1.465680126   5.232255329   5.753598846
H       11.612877425   5.231282938   6.495661694
H        9.435578196   5.231491779   2.545852436
K_POINTS AUTOMATIC
1 1 16 0 0 0

----out---

End of self-consistent calculation (1st)


     Forces acting on atoms (Ry/au):

     Total force =     0.003197     Total SCF correction =     0.000003


     entering subroutine stress ...

          total   stress  (Ry/bohr**3)                   (kbar)     P=   -0.04
  -0.00000100   0.00000000  -0.00000056         -0.15      0.00     -0.08
   0.00000000  -0.00000123   0.00000000          0.00     -0.18      0.00
  -0.00000056   0.00000000   0.00000137         -0.08      0.00      0.20

CELL_PARAMETERS (alat= 40.50311907)
   0.999975086   0.000000000   0.000000000
   0.000000000   0.999969153   0.000000000
   0.000000000   0.000000000   0.180925314

End of self-consistent calculation (23st)

Forces acting on atoms (Ry/au): Total force = 0.005428 Total SCF correction
= 0.000022 entering subroutine stress ... total stress (Ry/bohr**3) (kbar)
P= 0.39 0.00000356 0.00000000 -0.00000051 0.52 0.00 -0.07 0.00000000
0.00000351 0.00000000 0.00 0.52 0.00 -0.00000051 0.00000000 0.00000096
-0.07 0.00 0.14 CELL_PARAMETERS (alat= 40.50311907) 0.805107566 0.000000000
0.000000000 0.000000000 0.809022136 0.000000000 0.000000000 0.000000000
0.181542885
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