[Wien] optimize volume + min_lapw

[Peter Blaha]

When you want to optimize Volume, c/a and internal parameters you must:

a) run x optimize for volume-optimization. This produces a series of
    "volume-struct-files" (with constant c/a)
b) Now take the first of those volume-struct files, copy them to "case_initial.struct"
    and run   x optimize again, but this time with c/a optimization.
    edit the resulting optimize.job script and comment run_lapw; but
    uncomment the min_lapw  line. The find the min c/a (lowest energy) for
    this volume (it will automatically have optimized internal parameters)
c) Do this for every volume and finally plot the "best c/a-results" for
    each volume.

In the next WIEN2k version there will be a contributed tool which does this
automatically for you.

Tarik Ouahrani schrieb:
> 
> Thank you for your answer, I know the procedure that you offered to me, 
> my problem is that I have a curve Energy (Volume), and I want to get c/a 
> and u for each Vi depending on the pressure ,
> 
> any suggestion !!
> cordialy Tarik
> 
> 
> 
> 
> 
> ------------------------------------------------------------------------
> Date: Wed, 14 Jan 2009 13:40:03 +0530
> From: susanta.phy at gmail.com
> To: wien at zeus.theochem.tuwien.ac.at
> Subject: Re: [Wien] optimize volume + min_lapw
> 
> please do volume optimisation first depending upon your crystal 
> structure, i.e. vary volume or c/a or whatever
> you like and then run scf and when it converges you ll find how much 
> force in respective atom(s) and then you
> can decide the lattice to relax by running min -I -J "run_lapw -I -fc 
> 1.0 -i 40.
> 
> so far as i know you can't do both the job simultaneously, so optimise 
> volume  and get lattice constants and
> then you can force minimise by relaxing the lattice.
> 
> On Wed, Jan 14, 2009 at 1:32 AM, Tarik Ouahrani 
> <tarik_ouahrani at hotmail.com <mailto:tarik_ouahrani at hotmail.com>> wrote:
> 
> 
> 
>     Dear SUSANTA K MOHANTA
> 
>     Thanks a lot for your reply, looking at my script, I have already x
>     dstart uncomment, I don't have spin polarized nor complex system, I
>     don't want to use run_lapw or runsp_lapw, but   min -I -j "run_lapw
>     -I -fc 1.0 -i 40, exactly I would like to optimize at the same time
>     the volume and relax my compound that has internal position, So is
>     it possible to use the min_lapw script instead of run_lapw -ec
>     0.0001,  wathever you have another suggestion, I'll be thankful in
>     advance
>     Sincerly 
> 
> 
>          
> 
> 
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> 
> -- 
> SUSANTA K MOHANTA
> RESEARCH SCHOLAR
> DEPT.OF PHYSICS
> IIT KHARAGPUR
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-- 

                                       P.Blaha
--------------------------------------------------------------------------
Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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