[CP2K:9582] convergence problems when melting SiC at high pressure

[hut... at chem.uzh.ch]

Hi

is that the band gap of your system at that pressure?

Also, you say "the ab-initio molecular dynamics at NVE does not converge after several hundred steps"
Does that mean, after several hundred MD steps, the SCF is not converging anymore,
or the SCF did not converge within several hundred steps?

regards

Juerg Hutter
--------------------------------------------------------------
Juerg Hutter                         Phone : ++41 44 635 4491
Institut für Chemie C                FAX   : ++41 44 635 6838
Universität Zürich                   E-mail: hut... at chem.uzh.ch
Winterthurerstrasse 190
CH-8057 Zürich, Switzerland
---------------------------------------------------------------

-----cp... at googlegroups.com wrote: -----
To: cp... at googlegroups.com
From: Fernan Saiz 
Sent by: cp... at googlegroups.com
Date: 10/24/2017 05:14PM
Subject: Re: [CP2K:9582] convergence problems when melting SiC at high pressure

Hi,
The band gap of beta-SiC is 2.36 eV. What are parameters could be adjusted?

Thanks,

- Fernan
 
On Tue, Oct 24, 2017 at 8:46 AM,  <hut... at chem.uzh.ch> wrote:
Hi
 
 what do you expect for the band gap of this system?
 For small band gap systems you might need to adjust
 your simulation methods.
 
 regards
 
 Juerg Hutter
 --------------------------------------------------------------
 Juerg Hutter                         Phone : ++41 44 635 4491
 Institut für Chemie C                FAX   : ++41 44 635 6838
 Universität Zürich                   E-mail: hut... at chem.uzh.ch
 Winterthurerstrasse 190
 CH-8057 Zürich, Switzerland
 ---------------------------------------------------------------
 
 -----cp... at googlegroups.com wrote: -----
 To: cp2k <cp... at googlegroups.com>
 From: Fernan Saiz
 Sent by: cp... at googlegroups.com
 Date: 10/22/2017 08:34PM
 Subject: [CP2K:9574] convergence problems when melting SiC at high pressure
 
 Hello,
 I am studying the melting of a 256-atom SiC system at high pressures using the Z-method. I face the problem that when the pressure is around 10 o 20 GPa (obtained by reducing 1% the simulation cell size), the ab-initio molecular dynamics at NVE does not converge after several hundred steps. I tried reducing the timestep to 0.05 fs with a cutoff of 800 Ry for an initial temperature of 9000 K, which after a few hundred steps goes down to to some 4000 K and the system starts to melt. However, this system does not converge even though I used the CG minimizer with a eps_max 1.0E-6 for the inner and outer loops, the preconditioner FULL_ALL with the PADE functional. Input script file is attached.
 
 I was wondering if I could receive any useful piece of advice.
 
 Best regards,
  - Fernan Saiz
 Department of chemistry
 Imperial College London
 
   --
  You received this message because you are subscribed to the Google Groups "cp2k" group.
  To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+uns... at googlegroups.com.
  To post to this group, send email to cp... at googlegroups.com.
  Visit this group at https://groups.google.com/group/cp2k.
  For more options, visit https://groups.google.com/d/optout.
 
 
 [attachment "sic.inp" removed by Jürg Hutter/at/UZH]
 

 --
 You received this message because you are subscribed to a topic in the Google Groups "cp2k" group.
 To unsubscribe from this topic, visit https://groups.google.com/d/topic/cp2k/Zix1oKixhhA/unsubscribe.
 To unsubscribe from this group and all its topics, send an email to cp2k+uns... at googlegroups.com.
 To post to this group, send email to cp... at googlegroups.com.
 Visit this group at https://groups.google.com/group/cp2k.
 For more options, visit https://groups.google.com/d/optout.
 
  
  -- 
 You received this message because you are subscribed to the Google Groups "cp2k" group.
 To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+uns... at googlegroups.com.
 To post to this group, send email to cp... at googlegroups.com.
 Visit this group at https://groups.google.com/group/cp2k.
 For more options, visit https://groups.google.com/d/optout.