[Pw_forum] metal optimization tricks and constraining in slab

[David Foster]

Thank you Paolo and Axel

I would appreciate it if anybody could guide me about my questions.


Regards

David Foster

Ph.D. Student of Chemistry

--------------------------------------------
On Fri, 4/11/14, Paolo Giannozzi <paolo.giannozzi at uniud.it> wrote:

 Subject: Re: [Pw_forum] metal optimization tricks and constraining in slab
 To: "PWSCF Forum" <pw_forum at pwscf.org>
 Date: Friday, April 11, 2014, 12:16 PM
 
 On Fri, 2014-04-11 at 09:36 -0700,
 David Foster wrote:
 
 > I have emailed this message two times former (...) but
 
 > I didn't received them in my mail box, so, I think it 
 > has not been sent to any member. 
 
 think twice ... I received both
 
 P.
 
 > I repeat it again, and sorry for inconvenience.
 > 
 > 
 >  
 > 
 > Dear Users and supporters
 > 
 > "....Thank you for your quick answers...."
 > 
 > I have two questions:
 > 
 > 1- I prepared 3*3*3 bulk Pd super-cell, and used
 "vc-relax". The relaxation needed
 > 
 >    more than 200 iteration. I finally relaxed
 it with restarting command. Please help
 >    
 >    me in setting following parameters for
 fast relaxation for metals:
 >    
 >    a- degauss (I think increasing it helps
 for fast coarse optimization, but after it
 >    
 >       needs more fine
 optimization.
 >       with increasing it, does
 it need more "nbnd"?)
 > 
 >    b-mixing beta ( in my calculation, I set
 it to 0.3, but I got very fluctuation in optimization.
 > 
 >      does increasing it helps
 optimization speed?)
 > 
 >   c- I prepared input by a program that
 saves the structure in cif format. I used the coordination
 > 
 >      with "crystal" card. is it true?
 > 
 > 2- I prepared 5 layers Pd slab and should fix two
 layers' coordination, but I don't know how.
 >     I read input style help but
 confused.
 > 
 > Thanks again
 > 
 > 
 > 
 > 
 > Regards
 > 
 > David Foster
 > 
 > Ph.D. Student of Chemistry
 > _______________________________________________
 > Pw_forum mailing list
 > Pw_forum at pwscf.org
 > http://pwscf.org/mailman/listinfo/pw_forum
 
 -- 
 Paolo Giannozzi, Dept.
 Chemistry&Physics&Environment, 
 Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
 Phone +39-0432-558216, fax +39-0432-558222 
 
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