[CP2K-user] [CP2K:13447] Is it possible to run a Andressui or Fattebert Solvation Model with Molecular Dynamics?

[Dev Rana]

Hi Matthias,

Thank you for your input. I understand that as the distance from C1 (carbon 
#1) to C2 (carbon #2) increases, the band gap decreases until only the 
valence electrons remains. When the distance between atoms becomes short, 
the electrons converge into the conduction band which allows a bond to form 
with overlapping electrons. Therefore, since my electrons were so far 
apart, they had no band gap to overcome. I understand your rationale for 
using a spin polarized run or smearing, and I have tried this using a 6 
membered carbon ring, instead. i.e. all 6 atoms are close. Using SCCS & MD, 
it tells me that I need a stress tensor enabled. So I turn it on, then it 
says that SCCS is not configured for using the stress tensor. Therefore, I 
can't really run SCCS with MD, unless I use a SCF OT method. 

I guess I just don't understand how to run SCCS and MD with my system in 
which I'd like to see a reaction occurring between the 6 carbon atoms as 
they react into a ring or chain. What would you suggest?

I apologize for the many questions, I'm a complete newbie with this stuff, 
with very little guidance as I am self-teaching these topics. 

Best Regards,
Dev

On Thursday, June 4, 2020 at 4:54:09 AM UTC-4, Matthias Krack wrote:
>
> Dev,
>
>  
>
> your setup of a system of six separated carbon atoms does not have a band 
> gap and the addition of an implicit solvent won’t change that most likely. 
> The problem should show up already for a single isolated carbon atom which 
> you can converge either as a triplet within a spin polarized run (LSD and 
> MULTIP 3) or with smearing, i.e. with a fractional occupation of 2/3 for 
> the three degenerated C 2p orbitals. The latter approach works only with 
> diagonalization (try broyden_mixing).
>
>  
>
> Matthias 
>
>  
>
> *From:* c... at googlegroups.com <c... at googlegroups.com> *On Behalf Of *Dev 
> Rana
> *Sent:* Mittwoch, 3. Juni 2020 20:49
> *To:* cp2k <c... at googlegroups.com>
> *Subject:* Re: [CP2K:13447] Is it possible to run a Andressui or 
> Fattebert Solvation Model with Molecular Dynamics?
>
>  
>
> Thank you for the confirmation Matthias! Would you be able to look at my 
> input file? I'm having trouble with SCF convergence and my Andreussi model 
> set up. 
>
>  
>
> I'm trying to simulate 6 carbon atoms randomly placed as they migrate 
> through a molten Al system, using MD. Using the solvation model, I've set 
> up my 6 C atoms and have a dieletric constant of 80. I'm also attaching my 
> latest output file. 
>
>  
>
> I was originally using Diagonalization method for the SCF, but the 
> convergence column was migrating over 1. 
>
> I then tried using OT with minimizer DIIS, Full_ALL preconditioner and 
> 0.001 energy_gap, as recommended for OT, and it stays below 1, however it 
> never converges. 
>
>  
>
> I'm also running this simulation without a solvation model using a full 
> system of 256 Al atom and 6 carbon atoms randomly placed in the system for 
> comparison, with no issues of convergence, i.e. each SCF converges within 
> 24-30 steps with each step taking about 22 seconds. 
>
>  
>
> Thank you so much for all your help thus far! I really appreciate it!
>
>  
>
> Best Regards,
>
> Dev
>
> On Wednesday, June 3, 2020 at 12:42:32 PM UTC-4, Matthias Krack wrote:
>
> Yes.
>
>  
>
> *From:* c... at googlegroups.com <c... at googlegroups.com> *On Behalf Of *Dev 
> Rana
> *Sent:* Mittwoch, 3. Juni 2020 18:19
> *To:* cp2k <c... at googlegroups.com>
> *Subject:* [CP2K:13443] Is it possible to run a Andressui or Fattebert 
> Solvation Model with Molecular Dynamics?
>
>  
>
> As the question in the subject suggests, is it possible to run a solvation 
> model with MD?
>
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