[Wien] optimization of an orthorhombic cell

[Laurence Marks]

I did not write notes on cell optimizations, just MSR1a. Swamped.

---
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody
else has thought", Albert Szent-Gyorgi
http://www.numis.northwestern.edu
Corrosion in 4D http://MURI4D.numis.northwestern.edu
Partner of the CFW 100% gender equity project, www.cfw.org/100-percent
Co-Editor, Acta Cryst A


On Oct 12, 2017 17:05, "Dr. K. C. Bhamu" <kcbhamu85 at gmail.com> wrote:

> Dear Prof. Marks,
>
> I read your optimization notes for orthorhombic cell and tried to optimize
> an orthorhombic cell but I could not obtain an optimization plot.
>
>
> So I am following the standard procedure as below taken from your
> suggestion in the mailing list https://www.mail-archive.com/w
> ien at zeus.theochem.tuwien.ac.at/msg06932.html
> <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.mail-2Darchive.com_wien-40zeus.theochem.tuwien.ac.at_msg06932.html&d=DwMFaQ&c=yHlS04HhBraes5BQ9ueu5zKhE7rtNXt_d012z2PA6ws&r=U_T4PL6jwANfAy4rnxTj8IUxm818jnvqKFdqWLwmqg0&m=CCwrrgUZT3FHbBbTKhyWl219yV58Vhv95TA_U_uQYds&s=3Z2BD0hubIJEMETcqg_8zHYeAIXe5P9S2fezgiH9Zgg&e=>)
> and have a queries:
>
> The procedure is a four-step task what I am following:
>
> The original lattice parameters were: a, b, c=16.763005, 24.803600,
> 16.320431  >> vol 6785.64777697697 bohr^3.
>
>
> 1.   VARY C/A RATIO with CONSTANT VOLUME and B/A (orthorh lattice)
>
> getting below optimized data:
>  ==========================================================
> Lowest point on X-axis is =  -1.615800
> Minimum value of B/A is =     1.455755
> Minimum value of ENE is =   -339059.104498 Ry
>  ==========================================================
> Value of A is =     16.85428 bohr  ;    8.91890 Ang
> Value of B is =     24.53569 bohr  ;   12.98373 Ang
> Value of C is =     16.40929 bohr  ;    8.68342 Ang
>  ==========================================================
> Initial value of  B/A is =          1.479663
> Conv. Unit Cell Vol =  6785.7557 bohr^3 ; **********Ang^
>
>
> 2.  Volume optimization using option 1 in "x optimize" and then
> calculating new volume from eplot option.
>
>
> Query: Step two is giving optimized volume but I do not know how to
> calculate lattices parameters from a single volume
> value for the next step "VARY C/A RATIO with CONSTANT VOLUME and B/A
> (orthorh lattice)"?
>
>
> The original cell volume and lattice parameters are mentioned at the
> beginning.
>
> and the new volume from step two is: 6815.3427 bohr^3
>
>
>
> The above same query is for the remaining process:
>
> 3. optimization of C/A
>
> 4. optimization of V.
>
>
> *5 At the final step I will do structural relaxation (min_.....).
>
>
> Could you please advice me how to proceed?
>
>
>
> Kind regards,
> Bhamu
>
>
>
>
>
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