[QE-users] vc-relax for getting polymer bond lengths gives error in overlap matrix

[MARIA CATERINA CEVALLOS BRENES]

El 06-08-2019 13:01, Paolo Giannozzi escribió:

> On Tue, Aug 6, 2019 at 8:36 PM MARIA CATERINA CEVALLOS BRENES <MARIA.CEVALLOS at ucr.ac.cr> wrote: 
> 
>> However, I'm still not getting the dimerization expected.
> 
> it's a known problem of DFT in simple GGA form: (almost) no dimerization in polyacetylene. The funny thing is that if you do the calculation with an unconverged k-point grid, you get a decent dimerization, that disappears if you push the convergence of k-points 
> 
> Paolo -- 
> 
> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
> Phone +39-0432-558216, fax +39-0432-558222
> 
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso [1])
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users

Do you recommend to use LDA instead or B3LYP? Which one will give me the
most accurate Peierls distortion's band gap and why? 

And also which pseudo-potential would you recommend me to use? 

Thanks :) 

  

Links:
------
[1] http://www.max-centre.eu/quantum-espresso
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.quantum-espresso.org/pipermail/users/attachments/20190806/5734505a/attachment.html>