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 > at 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
