[Pw_forum] vc-relax

Stefano Baroni baroni at sissa.it
Wed May 6 18:59:32 CEST 2009


why don't you let it be?
the calculated pressure is exceedingly small ..
SB

On May 6, 2009, at 8:23 AM, ali kazempoor wrote:

>
> Dear All
> I want to study an O vacancy in 2*2*3 supercell for TiO2. I use from  
> vc-relax to optimize the lattice constant either with atomic  
> relaxation. But from one week ago, the pressure evolved around  0.00  
> and dident go to zero .for example
>              (kbar)     P=    0.07
>              (kbar)     P=   -0.45
>              (kbar)     P=   -0.23
>              (kbar)     P=   -0.25
>              (kbar)     P=   -0.34
>              (kbar)     P=   -0.40
>              (kbar)     P=   -0.36
>              (kbar)     P=   -0.14
>              (kbar)     P=   -0.57
>              (kbar)     P=   -0.41
>              (kbar)     P=   -0.45
>              (kbar)     P=   -0.83
>              (kbar)     P=   -0.45
>              (kbar)     P=   -0.37
>              (kbar)     P=   -1.58
>              (kbar)     P=   -1.00
>              (kbar)     P=   -0.71
>              (kbar)     P=   -0.73
>              (kbar)     P=   -0.61
>              (kbar)     P=   -0.58
>              (kbar)     P=   -0.39
>              (kbar)     P=   -0.89
>              (kbar)     P=   -0.58
>              (kbar)     P=   -0.33
>              (kbar)     P=   -0.37
>              (kbar)     P=    0.59
>              (kbar)     P=   -0.42
>              (kbar)     P=   -0.61
>              (kbar)     P=   -1.22
>              (kbar)     P=   -1.68
>              (kbar)     P=   -0.23
>              (kbar)     P=   -0.20
>              (kbar)     P=   -0.17
>              (kbar)     P=   -0.39
>              (kbar)     P=   -0.29
>              (kbar)     P=   -0.76
>              (kbar)     P=   -0.30
>              (kbar)     P=   -0.24
> what can I do for this problem?
> Here is input file:
>
>
>
> &control
>    calculation = 'vc-relax'
>    restart_mode='restart',
>    prefix='rutile-71atom'
>    tstress = .true.
>    tprnfor = .true.
>    pseudo_dir = './',
>    outdir='/ptmp/javad/scratch/'
> 	nstep=1000,
> 	dt=100,
> /
> &system
>    ibrav=  6 , celldm(1) =17.36,celldm(3)=0.9663585,  nat= 71, ntyp=  
> 2,
>    ecutwfc =35.0,ecutrho=400
> /
> &electrons
>    diagonalization=''
>    mixing_mode = 'plain'
>    mixing_beta = 0.7
>    conv_thr =  1.0d-4
> /
> &IONS
> /
> &CELL
> cell_dynamics = 'damp-w',
> press=00.0	
> /
> ATOMIC_SPECIES
> Ti   43.0   Ti.pz-sp-van.UPF
> O    16.0   O.pz-van_ak.UPF
> ATOMIC_POSITIONS crystal
> Ti 0.00000000 0.00000000 0.00000000
> Ti 0.50000000 0.00000000 0.00000000
> Ti 0.00000000 0.50000000 0.00000000
> Ti 0.50000000 0.50000000 0.00000000
> Ti 0.00000000 0.00000000 0.33333333
> Ti 0.50000000 0.00000000 0.33333333
> Ti 0.00000000 0.50000000 0.33333333
> Ti 0.50000000 0.50000000 0.33333333
> Ti 0.00000000 0.00000000 0.66666667
> Ti 0.50000000 0.00000000 0.66666667
> Ti 0.00000000 0.50000000 0.66666667
> Ti 0.50000000 0.50000000 0.66666667
> Ti 0.25000000 0.25000000 0.16666667
> Ti 0.75000000 0.25000000 0.16666667
> Ti 0.25000000 0.75000000 0.16666667
> Ti 0.75000000 0.75000000 0.16666667
> Ti 0.25000000 0.25000000 0.50000000
> Ti 0.75000000 0.25000000 0.50000000
> Ti 0.25000000 0.75000000 0.50000000
> Ti 0.75000000 0.75000000 0.50000000
> Ti 0.25000000 0.25000000 0.83333333
> Ti 0.75000000 0.25000000 0.83333333
> Ti 0.25000000 0.75000000 0.83333333
> Ti 0.75000000 0.75000000 0.83333333
> O  0.65265000 0.15265000 0.00000000
> O  0.15265000 0.65265000 0.00000000
> O  0.65265000 0.65265000 0.00000000
> O  0.15265000 0.15265000 0.33333333
> O  0.65265000 0.15265000 0.33333333
> O  0.15265000 0.65265000 0.33333333
> O  0.65265000 0.65265000 0.33333333
> O  0.15265000 0.15265000 0.66666667
> O  0.65265000 0.15265000 0.66666667
> O  0.15265000 0.65265000 0.66666667
> O  0.65265000 0.65265000 0.66666667
> O  0.34735000 0.34735000 0.00000000
> O  0.84735000 0.34735000 0.00000000
> O  0.34735000 0.84735000 0.00000000
> O  0.84735000 0.84735000 0.00000000
> O  0.34735000 0.34735000 0.33333333
> O  0.84735000 0.34735000 0.33333333
> O  0.34735000 0.84735000 0.33333333
> O  0.84735000 0.84735000 0.33333333
> O  0.34735000 0.34735000 0.66666667
> O  0.84735000 0.34735000 0.66666667
> O  0.34735000 0.84735000 0.66666667
> O  0.84735000 0.84735000 0.66666667
> O  0.40265000 0.09735000 0.16666667
> O  0.90265000 0.09735000 0.16666667
> O  0.40265000 0.59735000 0.16666667
> O  0.90265000 0.59735000 0.16666667
> O  0.40265000 0.09735000 0.50000000
> O  0.90265000 0.09735000 0.50000000
> O  0.40265000 0.59735000 0.50000000
> O  0.90265000 0.59735000 0.50000000
> O  0.40265000 0.09735000 0.83333333
> O  0.90265000 0.09735000 0.83333333
> O  0.40265000 0.59735000 0.83333333
> O  0.90265000 0.59735000 0.83333333
> O  0.09735000 0.40265000 0.16666667
> O  0.59735000 0.40265000 0.16666667
> O  0.09735000 0.90265000 0.16666667
> O  0.59735000 0.90265000 0.16666667
> O  0.09735000 0.40265000 0.50000000
> O  0.59735000 0.40265000 0.50000000
> O  0.09735000 0.90265000 0.50000000
> O  0.59735000 0.90265000 0.50000000
> O  0.09735000 0.40265000 0.83333333
> O  0.59735000 0.40265000 0.83333333
> O  0.09735000 0.90265000 0.83333333
> O  0.59735000 0.90265000 0.83333333
> K_POINTS automatic
> 3 3 2   1 1 1
> thanks alot
> Ali Kazempour,Isfahan University of Technology
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---
Stefano Baroni - SISSA  &  DEMOCRITOS National Simulation Center -  
Trieste
[+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype)

La morale est une logique de l'action comme la logique est une morale  
de la pensée - Jean Piaget

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