[Pw_forum] optimization of any structure

[Prasenjit Ghosh]

Dear Sathya,

Please go through the pages in the following link:

http://www.quantum-espresso.org/wiki/index.php/Tutorials_and_Examples.

It will help you a lot with the basics involved in performing a calculation.

As far as finding the cell parameters are concerned, you can do it in two
ways using pw.x:

(1) using calculation='vc-relax', which is quite tricky to use

(2) by relaxing manually, do "relax" or "scf" cal. for different sets of
cell parameters ( ususally around +/- 3-4 % of the experimentally one). Use
ev.x to fit the data to some equation of state and obtain the optimized
values of cell parameters.

With regards,
Prasenjit.

2008/7/28 sathya subramanyan <sathya_sheela1985001 at rediffmail.com>

>   Dear All,
>           I know this is a very basic question but I would like to know
> which example; Example03 or VCSexample should be used to optimize any
> structure. Example03 gives the optimized positions but not the cell
> dimensions while VCSexample(runs for more than a day) gives both the
> optimized cell dimensions and cell positions (but not close to the
> experimental ). Please do help. Thank you in advance.
>  SATHYA SHEELA.S
> Grad. Student
> Department of Physics
> National Institute of Technology
> Tiruchirapalli - 620015
> India
>
> [image: 578*38-d]<http://adworks.rediff.com/cgi-bin/AdWorks/click.cgi/www.rediff.com/signature-home.htm/1050715198@Middle5/2252067_2244406/2247149/1?PARTNER=3&OAS_QUERY=null>
> _______________________________________________
> Pw_forum mailing list
> Pw_forum at pwscf.org
> http://www.democritos.it/mailman/listinfo/pw_forum
>
>


-- 
PRASENJIT GHOSH,
POST-DOC,
ROOM NO: 265, MAIN BUILDING,
CM SECTION, ICTP,
STRADA COSTERIA 11,
TRIESTE, 34104,
ITALY
PHONE: +39 040 2240 369 (O)
+39 3807528672 (M)
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.democritos.it/pipermail/pw_forum/attachments/20080729/d9286ea8/attachment.htm