[Pw_forum] Geometry (Structural) Optimization

[Mofrad, Amir Mehdi (MU-Student)]

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<mailto: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


_______________________________________________
Pw_forum mailing list
Pw_forum at pwscf.org<mailto:Pw_forum at pwscf.org>
http://pwscf.org/mailman/listinfo/pw_forum

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20151022/7de85ba0/attachment.html>