[Pw_forum] MoS2 -monolayer input -

[Sohail Ahmad]

Dear QE users

I am working on MoS2 which is hexagonal layered structure having 2 Mo and 4 S atoms
i wish to study now only a single layer (one Mo and two S). 
The only thing i understand that i 
will have to increase c axis to prevent interaction 
between the layers.
But when i do so i
 realise that all bond length got stretched.

both
 the two input file (bulk and monolayers are attached) 
pls compare the two inputs,
 i got the results for bulk perfectly comparable to the experiment when i run for mono sometimes it doesnot and sometimes it gives unwanted 20-30 GB files

I dont know where is the mistake

Thanks in Advance for any help

Sohail
 Ahmad
King Khalid University
Saudi Arabia

-----
Monolayer input

&control
  calculation = 'scf',
  restart_mode = 'from_scratch',
  prefix = 'MoS1l',
  pseudo_dir = '/home/sandeep/espresso-4.2.1/pseudo',
  outdir = './OUT',
 /
 &system
    ibrav = 0, a= 3.16,c= 6.15,
    cosac= 0.0, cosbc= 0.0, cosab= -0.5,
  nat = 3,
  ntyp = 2,
  ecutwfc = 70,
  ecutrho = 300,
  nbnd = 20,
  occupations = 'smearing', smearing = 'gaussian', degauss = 0.001,
  nspin = 2,
  starting_magnetization(1) = 0.5d0,
 /
  &electrons
  mixing_beta = 0.3,
  conv_thr = 1.0d-9,
 /
ATOMIC_SPECIES
Mo  95.96  Mo.pw91-n-van.UPF
S   32.06  S.pw91-van_ak.UPF
CELL_PARAMETERS
 {hexagonal}
 1.00000000           0.00000000          0.00000000
-0.50000000           0.86602540          0.00000000
 0.00000000           0.00000000          7.78000000 
ATOMIC_POSITIONS {Angstrom}
Mo  1.58000000  0.91221343  3.07250000
S   1.58000000 -0.91221343  1.47480000
S   1.58000000 -0.91221343  4.67260000
K_POINTS AUTOMATIC
4 4 4 1 1 1 
--------
bulk input
&control
  calculation = 'scf',
  restart_mode = 'from_scratch',
  prefix = 'MoSb8',
  pseudo_dir = '/home/sandeep/espresso-4.2.1/pseudo',
  outdir =
 './OUT',
 /
 &system
  ibrav = 4, celldm(1) = 6.0281946, celldm(3) = 3.89, nat = 6, ntyp = 2,
  ecutwfc = 70,
  ecutrho = 300,
  nbnd = 30,
  occupations = 'smearing', smearing = 'gaussian', degauss = 0.001,
  nspin = 2,
  starting_magnetization(1) = 0.1d0,
 /
 &electrons
  mixing_beta = 0.3,
  conv_thr = 1.0d-9,
 /
ATOMIC_SPECIES
Mo  95.96  Mo.pw91-n-van.UPF
S   32.06  S.pw91-van_ak.UPF
ATOMIC_POSITIONS {crystal}
Mo  0.33333333  0.66666667  0.25000000
Mo  0.66666667  0.33333333  0.75000000
S   0.33333333  0.66666667  0.62000000
S   0.66666667  0.33333333  0.12000000
S   0.66666667  0.33333333 -0.62000000
S   0.33333333  0.66666667 -0.12000000
K_POINTS AUTOMATIC
8 8 8 1 1
 1
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