[Wien] Optimization of orthorhombic and monoclinic structure.

[Lyudmila Dobysheva]

21.09.2020 11:18, Ramsewak Kashyap wrote:
> I have compared both two method viz. Vol > b/a > c/a and 
> 3-D variation. I have found the following results :
> A) Taking 27 structure variation with 1% change (3D variation option)-
>       TiNi_without_vol optimization :
> a=7.804420bohr ;4.129921208Ang
> b=5.365367bohr ;    2.839229944Ang
> c=8.727774bohr ; 4.6185391018Ang
> 
> TiNi_after_vol optimization:
> a = 7.884109bohr ;	4.172090810 Ang
> b = 5.294220bohr ;	2.801580573 Ang
> c = 8.839241bohr; 4.677524898Ang
> 
> B) With Vol > b/a > c/a optimization :
> Value of A is =      8.16927 bohr  ;    4.32299 Ang
> Value of B is =      5.13974 bohr  ;    2.71984 Ang
> Value of C is =      8.77242 bohr  ;    4.64217 Ang
> 
> 1. Which one should  be taken as optimized parameters?
> 2. How much this parameter difference affects  EFG calculation i.e. 
> sensitivity of EGF calculation??

1. I'd say that nobody can answer you. You are to analyze yourself. 
Check the convergences, compare the energies (:ENE).
Lifehack: you can gather all the calculations (scf files) into one 
directory and try parabolfit for all of them. Pay attention that all scf 
be read, as they have slightly different names which ,maybe, do not pass 
through the parabolfit's mask. (Of course, all calculations has to be 
done at the same parameters)
2. In my practice, EFG greatly depends on the lattice parameters and 
atomic positions, but this may depend on the system. You can see the 
difference yourself just look in SCFs obtained.

Best wishes
Lyudmila Dobysheva
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