[Wien] optimization of an orthorhombic cell

[Dr. K. C. Bhamu]

I read it from:
http://susi.theochem.tuwien.ac.at/reg_user/textbooks/Optimization-Notes.pdf

anyway, I need guidance how to find the optimized a, b, c from the process
mentioned in the previous email.



Bhamu

On Fri, Oct 13, 2017 at 3:38 AM, Laurence Marks <L-marks at northwestern.edu>
wrote:

> 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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