[Wien] Constraining position in case.inM

[Peter Blaha]

> I have another query;
> 
> If I want to vary only x coordinate while maintaining y & Z coordinate 
> to the same value of x, what should I do?
> 
> As an example in the desired structure, I want to have (x, x,x) & want 
> to vary the only x, what should be the process?

This depends on your structure and symmetry. Most likely, the position 
(x,x,x) is "fixed" by symmetry to have 3 equal values. You can see this 
eg. from your forces, that this atom has only ONE force component (LM=1 
0) and a local rotation matrix putting the z-axis into 111 direction.

In such a case you have to break symmetry. This means: in a new 
directory, change (x,x,x) manually to (x,y,y) (and similary to 
equivalent atoms if Mult gt.1). Then do    init_lapw.
(It could be that positions become inequivalent by this procedure and 
you will get more non-equivalent atoms).
Then check your symmetry (eg. in case.outputs, if the position has a 
symmetry such that y and z must be identical, or if they can move freely 
(check eg. the LM-list in case.outputs: if they include 3 L=1 terms, 
they are independent, if they have only 2 L=1 values, they are fixed to 
be identical.

This will allow to manipulate x and y,y (or y,z) individually.
> 
> with regards,
> 
> 
> 
> On Sat, 27 Mar 2021 at 12:15, Peter Blaha <pblaha at theochem.tuwien.ac.at 
> <mailto:pblaha at theochem.tuwien.ac.at>> wrote:
> 
>     Basically the steps are correct.
> 
>     Only for step (4): if min_lapw works well for your case, you may
>     continue. However, remember that the recommended way to optimize
>     positions is now:
>     run_lapw -min
> 
>     Regards
> 
>     Am 27.03.2021 um 06:47 schrieb shamik chakrabarti:
>      > Dear Wien2k users,
>      >
>      >                            If I want to keep some positions of
>     atoms of
>      > a primitive cell during force minimization should I follow the
>     following
>      > steps;
>      > (1) put 0 by replacing 1 for the atoms (for all the coordinates
>     x, y, z)
>      > which I want to remain fixed in case.inM
>      > (2) remove file case.tmpM
>      > (3) x pairhess
>      > (4) min_lapw
>      >
>      > Looking forward to your reply in this regard.
>      >
>      > with regards,
>      > --
>      > Dr. Shamik Chakrabarti
>      > Research Fellow
>      > Department of Physics
>      > Indian Institute of Technology Patna
>      > Bihta-801103
>      > Patna
>      > Bihar, India
>      >
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>     -- 
>     --------------------------------------------------------------------------
>     Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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> 
> 
> 
> -- 
> Dr. Shamik Chakrabarti
> Research Fellow
> Department of Physics
> Indian Institute of Technology Patna
> Bihta-801103
> Patna
> Bihar, India
> 
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-- 
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WIEN2k: http://www.wien2k.at
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