[Pw_forum] fluctuation in SCF energies of CO adsorbed on Pd110

[David Foster]

Dear Prof. Giannozzi

Thank you for your comments. I will correct the inputs according to your ideas.


Regards

David Foster

Ph.D. Student of Chemistry

--------------------------------------------
On Wed, 4/23/14, Paolo Giannozzi <paolo.giannozzi at uniud.it> wrote:

 Subject: Re: [Pw_forum] fluctuation in SCF energies of CO adsorbed on Pd110
 To: "PWSCF Forum" <pw_forum at pwscf.org>
 Date: Wednesday, April 23, 2014, 7:18 PM
 
 I would increase degauss by at least
 a factor 10.
 The kind of behavior you have is typical of metals
 that are not treated as such. degauss=0.001 is
 very small and it may not have enough effect.
 
 For a Gamma-only calculation, K_POINTS gamma is 
 faster (allows the usage of memory- and cpu-saving 
 tricks). 1000 bands (instead of 1300) should be 
 sufficient. For a first test you should use smaller
 cutoffs.
 
 Paolo
 
 On Sun, 2014-04-20 at 09:20 -0700, David Foster wrote:
 > Dear users
 > 
 > I have prepared an input for interaction between CO and
 Pd(110). I optimized 3*3*3 supercell of Pd bulk, and then
 cleaved a 110 surface and constructed a slab. I inserted CO
 molecule which has been optimized with QE5.0.2 in it. Now, I
 try to optimize this mixed system (CO+Pd(110)).
 > 
 > My main problem is that in scf I see the fluctuation in
 energies. My input and output has been attached. In all
 calculations I used QE5.0.2 and the same USPP. I used PBE
 DFT in the PP. I used nspin=2 due to the presence of oxygen
 atom. I introduced start_magnetization for all species. I
 fixed three bottom layers in the cell. I used ibrav=14 to
 optimize bulk phase of Pd, and didn't change it in all
 computation.
 > I used degauss=0.001RY. In addition I used smearing
 technique for both bulk and slab.
 > 
 > The run is continuing, but I think finally, I will
 encounter with problem.
 > 
 > Any idea for rapid convergence and solve the issue in
 fluctuation energy is appreciated.
 > 
 > 
 > 
 > 
 > Regards
 > 
 > David Foster
 > 
 > Ph.D. Student of Chemistry
 > _______________________________________________
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 -- 
 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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