[Wien] structure optimization in WIEN2k

[Peter Blaha]

In the latest option there is a possibility to generate struct files for 
c and a variation simultaneously.

edit optimize.job (and uncomment/adapt the "min_lapw line", comment the 
"run_lapw" line.)

This way you simultaneously optimize the internal parameters for each 
pair of a and c.

PS: I do this in 2 steps, first with a rather small RKmax+ k-mesh; then 
(using the "preoptimized" structures with a better RKmax and k-mesh). 
But this requires some experience and "feeling" for proper parameters.

Hong Jiang schrieb:
> Dear WIEN2k users,
> I have a question about the structure optimization using WIEN2k. I want 
> to optimize a crystal structure, say, tetragonal ZrO2,
> which has three structural variables, the two lattice constants a, c,  
> and an internal variable d_z.  WIEN2k provides the functions of
>  (1) optimize volume with fixed c/a ratio
>  (2) Optimize c/a ratio with fixed volume
>  (3) optimize internal variables with fixed lattice constant,
> I guess taking different order of these optimization procedures would 
> lead to different results. Ideally I guess one should repeat these three 
> procedures
> for several times until convergence is reached.
> My questions are : are  there any empirical schemes to obtain the 
> optimized structure more efficiently ? Is the self-consistency really 
> necessary?
> If not,  which order should one take to obtain the most reliable results?
> 
> Thank you very much in advance!
> 
>   -Hong Jiang
> 
> 
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