[Pw_forum] very high pressure in scf

Fri May 27 08:44:05 CEST 2011

Do you know that there is a free tool converting input file from ab-init to PWscf format? You can download it from qe-forge.
http://qe-forge.org/frs/?group_id=10
I've never used it, but you can give it a try to see if you get the same PWscf input.

HTH

GS

Il giorno 27/mag/2011, alle ore 06.19, Sanjeev Gupta ha scritto:

> Dear Sir,
> 
> Thank you for kind reply.
> 
> Here i am attaching the input file of ABINIT which gives less pressure for same structure as i have taken in PWSCF (I mentioned in my previous mail). Please look in this matter and suggest me.
> 
> 
> #********** input file from abinit code...... 
> 
> ndtset     1
> acell       5.30  5.30  19.65615823
> dilatmx   1.02
> toldfe      1.0d-6
> #Common data****************
> ixc         11
> kptopt    1
> nshiftk   1
> shiftk     0.0  0.0  0.5
> ngkpt     6 6 6
> ecut       30
> ecutsm  0.5
> ntime     50
> iscf       7
> nstep    50
> nband   32
> angdeg 90  90  120
> spgroup 166
> brvltt     0
> occopt   3
> tsmear   0.01
> natom    9
> typat      1 2 2 1 2 2 1 2 2
> ntypat     2
> znucl      26 7
>  xred
>  -1.8503717077E-17 -1.8503717077E-17 -1.8503717077E-17
>  ...........
> ............
> ...........
>   3.3333333333E-01  6.6666666667E-01  2.2599217437E-01
> chkprim 0
> 
> 
> 
> 
> #****************************************************************************
>                                                                                                              1,1           Top
> 
> 
> On Fri, May 27, 2011 at 1:16 AM, Stefano de Gironcoli <degironc at sissa.it> wrote:
> I think the two structures are not the same, or some of the parameters have non equivalent 
> values.
> stefano
> 
> 
> On 05/26/2011 08:50 PM, Sanjeev Gupta wrote:
>> Dear Sir,
>> Thanks for reply.
>> 
>> 
>> On Thu, May 26, 2011 at 10:23 PM, Stefano de Gironcoli <degironc at sissa.it>wrote:
>> 
>>>  with this input the Fe-N distance is some 1.2 A... I'm pretty sure it
>>> cannot be the intended structure
>>> Are you sure the system is not in crystal coordinate ?
>>>  stefano
>>> 
>> Yes, its true that  while looking from xcrysden particularly the bond
>> lengths between the Fe-N and N-N  but i am very surprised why both ABINIT
>> and PWSCF code gives such vast Difference in calculated Pressure for the
>> identical geometry which is not cleared yet. Here the bond lenth Fe-N is
>> ~1.24Ang.
>> Please Suggest More.
>> 
>> 
>> 
>>> 
>> 
>>> 
>> 
>>> On 05/26/2011 04:13 PM, Sanjeev Gupta wrote:
>>> 
>>> Dear Maxim
>>> 
>>> Thank for kind reply.
>>> 
>>> My unit cell is as same in ABINIT  as in pwscf in Bohr  unit. In addition I
>>> am using the spacegroup 166   (R3(bar)M) space group with conventional unit
>>> cell rather than primitive unit cell the lattice parameter is taken as below
>>> 1. for abinit
>>> 
>>> a=5.359168252 Bohr
>>> b=5.359168252 Bohr
>>> c=20.08294707 Bohr
>>> 
>>> 2. for PWSCF
>>> 
>>> ibrav=4,
>>> celldm(1) = 5.359168242 Bohr
>>> celldm(3) = 3.7474
>>> 
>>> Part of my input file is :
>>> 
>>> PWSCF
>>> 
>>> &control
>>>     calculation = 'scf'
>>>     prefix='FeN2',
>>>     restart_mode='from_scratch',
>>>     outdir='./'
>>>     pseudo_dir = '/',
>>>     tstress = .true.
>>>     tprnfor = .true.
>>>     etot_conv_thr = 1.0d-5,
>>>     forc_conv_thr = 1.0d-4,
>>>  /
>>>  &system
>>>     ibrav=4,
>>>     celldm(1) = 5.359168242,
>>>     celldm(3) = 3.7474
>>>     nat=9,
>>>     ntyp=2,
>>>     nosym =.true.,
>>>     ecutwfc = 20,
>>>     ecutrho=200,
>>>     occupations='smearing',
>>>     smearing='m-p',
>>>     degauss=0.001,
>>>  /
>>>  &electrons
>>>      mixing_mode     = "local-TF",
>>>      mixing_beta     =  0.700000,
>>>      conv_thr        =  1.0d-10,
>>> /
>>> ATOMIC_SPECIES
>>> Fe  55.845  Fe.pbe-sp-van.UPF
>>> N   14.0067 N.pbe-van_ak.UPF
>>> ATOMIC_POSITIONS
>>> Fe    -1.8503717077E-17 -1.8503717077E-17 -1.8503717077E-17
>>> N     -1.8503717077E-17 -1.8503717077E-17  4.4000000000E-01
>>> 
>>> ..............................
>>> ............
>>> 
>>> N      3.3333333333E-01  6.6666666667E-01  2.2666666667E-01
>>> K_POINTS automatic
>>> 6 6 6 0 0 0
>>> 
>>> 
>>> Best Regards
>>> 
>>> 
>>> Sanjay D. Gupta
>>> Research Fellow
>>> Department of Physics,
>>> Bhavnagar University, Bhavnagar-364 022
>>> Gujarat, Mobile-9879666643email:guptasanjay_56 at yahoo.co.in
>>> 
>>> 
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>>> 
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§ Gabriele Sclauzero, EPFL SB ITP CSEA
   PH H2 462, Station 3, CH-1015 Lausanne

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