[Pw_forum] Geometry (Structural) Optimization

[Bahadır salmankurt]

Hi
---
&control
        calculation='relax',
        restart_mode='from_scratch',
        prefix='si',
pseudo_dir = '../pseudo',
        outdir='out',

*   tstress = .true.    tprnfor = .true.*
/
&system
        ibrav=  2,
        celldm(1) =10.14,
        nat=  2,
        ntyp= 1,
        ecutwfc =16,
/
&electrons
        conv_thr =  1.0d-10,
/
&ions
/

*&cell/*
ATOMIC_SPECIES
 Si  28.086 Si.pz-vbc.UPF
ATOMIC_POSITIONS
 Si 0.00 0.00 0.00
 Si 0.28 0.28 0.28
K_POINTS AUTOMATIC
4 4 4 1 1 1
----
in relax calculations, you must add *&cell . *Also, you can calculate
stress and force acting on atoms using *   tstress = .true. , tprnfor =
.true. *parameters.

I chanced atomic positions intentionally. Please run the code and see what
happen !

Bests

2015-10-22 18:34 GMT+03:00 Mofrad, Amir Mehdi (MU-Student) <
amzf5 at mail.missouri.edu>:

> Hi Sridhar,
>
> Thank you for your reply. I followed your instructions on only changing
> the task to both 'relax' and 'vc-relax' in my input file. However, I got
> the following error for both of them:
>
> task #         0
>      from  read_namelists  : error #         1
>       reading namelist ions
>
>
> Following a tutorial on the internet and according to the above error , at
> first, I only added the  namelist &ions and got an output (very small
> output). So Again I added other parameters in the &control namelist based
> on the same tutorial (without knowing what they are) and got another
> output. I was wondering if you would kindly take a look at my final input
> file and tell me what those parameters that I added are.
>
>
> Here is my input file:
>
>
> &control
>         calculation='relax',
>
>         nstep= 50,                                     <========== I
> added this
>
>         etot_conv_thr= 1.d-4,               <========== I added this
>
>         forc_conv_thr= 2.d-3,               <========== I added this
>         restart_mode='from_scratch',
>         prefix='si',
>         pseudo_dir = '../pseudo',
> /
>
> &system
>         ibrav=  2,
>         celldm(1) =10.187,
>         nat=  2,
>         ntyp= 1,
>         ecutwfc =16,
> /
>
> &electrons
>         conv_thr =  1.0d-10,
> /
>
> &ions
>
>         ion_dynamics = 'bfgs',                                   <==========
> I added this
>
>         pot_extrapolation= 'second_order',         <========== I added
> this
>
>         wfc_extrapolation= 'second_order',         <========== I added
> this
>
>         upscale = 100,                                                  <==========
> I added this
> /
> ATOMIC_SPECIES
>  Si  28.086 Si.pz-vbc.UPF
>
> ATOMIC_POSITIONS
>  Si 0.00 0.00 0.00
>  Si 0.25 0.25 0.25
>
> K_POINTS AUTOMATIC
> 4 4 4 1 1 1
>
>
> Thank you,
>
>
> Amir M. Mofrad
>
> University of Missouri
>
>
> ------------------------------
> *From:* pw_forum-bounces at pwscf.org <pw_forum-bounces at pwscf.org> on behalf
> of Sridhar Sadasivam <sridhu88 at gmail.com>
> *Sent:* Wednesday, October 21, 2015 6:51 PM
> *To:* PWSCF Forum
> *Subject:* Re: [Pw_forum] Geometry (Structural) Optimization
>
> Hi Amir,
> The calculation for geometry optimization does not require data from any
> previous scf runs - It is a separate calculation. You need to use the same
> pw.x program that you use for scf. But just change the calculation
> parameter in &control namelist to 'relax' or 'vc-relax'. Apart from that,
> your input file is quite similar to that for scf.
> Sridhar
> Purdue University
>
> On Wed, Oct 21, 2015 at 7:51 PM, Mofrad, Amir Mehdi (MU-Student) <
> amzf5 at mail.missouri.edu> wrote:
>
>> Hi all,
>>
>>
>>   I have done an SCF calculation on a silicon unit cell and I want to do
>> a structural (geometry) optimization next. The documentation for this
>> purpose was not that helpful and I have a couple of questions, for
>> instance should I use the data generated from the scf calculation or should
>> I define a thoroughly different input file for this calculation? What is
>> the command to do so? Is it the same as pw.x or something else?   Any help
>> would be appreciated.
>>
>>
>> Thank you,
>>
>>
>> Amir
>>
>>
>>
>> _______________________________________________
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>>
>
>
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>



-- 

Bahadır SALMANKURT
PhD student
Sakarya University, TURKEY
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