[Wien] Confusion regarding supercell calculation

[Gavin Abo]

As far as I recall, "x optimize" creates a range of struct files that 
you specify when running that program for searching for the optimized 
structure parameters.  The scf calculations are completed on each one.  
The energy and lattice parameter results generated from that are then 
fitted using WIEN2k's parabolfit_lapw (or by using another fitting 
program such as Origin) to interpolate/extrapolate values for the 
optimized parameters.  The program usually does not create a struct file 
with the optimized parameters.  Though, depending on how dense you make 
the optimization calculations, say a course set of 10 struct files or a 
fine set of say 100,000 struct files, a struct file close or identical 
to the optimization parameter may or may not be among them that the user 
could chose to use.  Although, it should be graphically checked if the 
data is fit well or not.  If the fit is well, then the fitted structure 
parameters could be manually taken to create a new struct file so that a 
calculation can be ran to get the electronic structure output with the 
optimized parameters.

I haven't tried WIEN2k 21.1's new optimize_abc_lapw that can be used for 
orthorhombic (3D) cases that is mentioned on the updates page [1] that 
the userguide mentions creates a optimize_abc_summary.out file (which 
should be possible to take the data from to a create optimized struct 
file using makestruct_lapw for example).

[1] http://susi.theochem.tuwien.ac.at/reg_user/updates/
[2] http://susi.theochem.tuwien.ac.at/reg_user/textbooks/usersguide.pdf

On 6/28/2021 12:36 PM, Anupriya Nyayban wrote:
> Dear experts and users,
> I have run the the volume optimization for the orthorhombic structure 
> with the option '1) vary volume with constant a:b:c ratio', also 
> edited the optimize.job by using 'dstart -p' and 'min -I -j "run_lapw 
> -I -fc 1.0 -i 40 -p"'. I have observed that the lattice parameters 
> (from the struct file) after the volume optimization do not match with 
> the lattice parameters corresponding to any of the optimized volumes 
> obtained from the equation of states. If the struct files are the 
> updated one after the volume optimization, why are the values different?
>
> Thank you!!
>
> -- 
> With regards
> Anupriya Nyayban
> Ph.D. Scholar
> Department of Physics
> NIT Silchar