[CP2K-user] [CP2K:13461] Is it possible to run a Andressui or Fattebert Solvation Model with Molecular Dynamics?

[Dev Rana]

Hi Matthias,

Ahh! Ok, this makes sense. I was trying to use NPT_F as the simulation we 
are trying to accomplish is for a real world system in which P (pressure at 
atmosphere) and T are actually held constant. Therefore I was using a 
thermostat and barostat with a large enough cell that it would not 
contribute to excessive pressures. I can try running NVT or NVE. 

On Thursday, June 4, 2020 at 4:53:37 PM UTC-4, Matthias Krack wrote:
>
> Hi Dev
>
>  
>
> a stress tensor is available with SCCS only in the current development 
> version of CP2K and not in any earlier version including the release 
> version 7.1. Note, that the stress tensor is only needed for MD ensembles 
> with a barostat like NpT, i.e. NVT or NVE should work also with earlier 
> versions.
>
>  
>
> HTH
>
>  
>
> Matthias
>
>  
>
> *From:* c... at googlegroups.com <javascript:> <c... at googlegroups.com 
> <javascript:>> *On Behalf Of *Dev Rana
> *Sent:* Donnerstag, 4. Juni 2020 18:26
> *To:* cp2k <c... at googlegroups.com <javascript:>>
> *Subject:* Re: [CP2K:13461] Is it possible to run a Andressui or 
> Fattebert Solvation Model with Molecular Dynamics?
>
>  
>
> 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. 
>
>  
>
> 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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