[CP2K-user] [CP2K:17184] Re: Problem with 2nd generation CPMD

[Onofrio Tau]

Hi Sam,
yes, of course. I set up more standard BOMD with ENSEMBLE NVT and 
DIAGONALIZATION with smear (look at my input file) and worked fine: it took 
more or less *30 steps to reach convergence* every AIMD step.

Then, I tried with ENSEMBLE NVT and OT (without smear obviously) and I got 
(MAX_SCF 200):






















* *** WARNING in qs_scf.F:598 :: SCF run NOT converged *** *** WARNING in 
qs_scf.F:598 :: SCF run NOT converged ***  *** SCF run converged in    79 
steps ***  *** SCF run converged in    72 steps ***  *** SCF run converged 
in    84 steps ***  *** SCF run converged in    53 steps ***  *** SCF run 
converged in    49 steps ***  *** SCF run converged in    48 steps ***  *** 
SCF run converged in    38 steps ***  *** SCF run converged in    40 steps 
***  *** SCF run converged in    38 steps ***  *** SCF run converged in   
 30 steps ***  *** SCF run converged in    23 steps ***  *** SCF run 
converged in    26 steps ***  *** SCF run converged in    27 steps ***  *** 
SCF run converged in    26 steps ***  *** SCF run converged in    26 steps 
***  *** SCF run converged in    23 steps ***  *** SCF run converged in   
 16 steps ***  *** SCF run converged in    16 steps ***  *** SCF run 
converged in    16 steps ***  *** SCF run converged in    18 steps ****
*   ...*

Though SCF run not converged for the first two AIMD steps, then it worked 
sometimes fine (SCF run converged in 16 steps, but not always!). Could be a 
possible solution.
N.B.: setting MAX_SCF below 200 (i.e., 50) makes SCF run not converged more 
than two initial AIMD steps.

Anyway, I'm looking for correctly set up SGCPMD as that found in the 
following works:
- Lan, Jinggang, Jürg Hutter, and Marcella Iannuzzi. "First-principles 
simulations of an aqueous CO/Pt (111) interface." *The Journal of Physical 
Chemistry C* 122.42 (2018): 24068-24076.
- Musso, Tiziana, et al. "Second generation Car-Parrinello MD: application 
to the h-BN/Rh (111) nanomesh." *The European Physical Journal B* 91.7 
(2018): 1-8.

However, I'm struggling with and I kindly need your help.
Kind regards.

Onofrio

Il giorno giovedì 16 giugno 2022 alle 09:58:41 UTC+2 wave... at gmail.com ha 
scritto:

> Hi Onofrio
>
> Question: have you set this up and run a more standard simulation to work 
> out the convergence first?
>
> If I guess, it's probably Cu as a transition metal with d-orbitals that is 
> difficult (I am suffering with Au).
>
> Kind Regards
>
> Sam 
> On Wednesday, June 15, 2022 at 3:20:20 PM UTC+2 onofr... at gmail.com wrote:
>
>> Dear CP2K community,
>>
>> I'm new to CP2K and I'm trying to set up a second-generation 
>> Car-Parrinello (SGCP) MD simulation. I have started with a geometrically 
>> optimized system of toluene adsorbed on a 3-layer Cu slab (8x6). I would to 
>> know what sections/keywords in the input file must be used to correctly set 
>> up a SGCPMD simulation and, possibly, the best settings to improve the 
>> speed of such simulations since I have not found any related tutorial (but 
>> only few things in the cp2k google group). 
>> If I well understood, it has to be turn on the Langevin dynamics section 
>> in combination with the OT method. For example:
>>
>> &FORCE_EVAL
>>   ...
>>   &DFT
>>     ...
>>     &QS
>>       METHOD GPW
>>       EXTRAPOLATION ASPC
>>       EXTRAPOLATION_ORDER 3
>>       EPS_DEFAULT 1.0E-10
>>     &END QS
>>     ...
>>     &SCF
>>     ...
>>       &OT
>>         PRECONDITIONER FULL_SINGLE_INVERSE   ! or FULL_KINETIC
>>         MINIMIZER DIIS
>>         N_DIIS 7
>>       &END OT
>>       &OUTER_SCF
>>         MAX_SCF 3
>>         EPS_SCF 1.0E-05
>>       &END OUTER_SCF    
>>     ...
>>     &END SCF
>>     ...
>>   &END DFT
>>   ...
>> &END FORCE_EVAL
>>
>> &MOTION
>>   &MD
>>     ENSEMBLE LANGEVIN
>>     ...
>>     &LANGEVIN
>>       GAMMA 0.001
>>     &END LANGEVIN
>>     ...
>>   &END MD
>>   ...
>> &END MOTION
>>
>> Is it correct? To follow what I just mentioned, I prepared an input file 
>> (attached below) based on sections/keywords defined just above and I got 
>> from the output file (attached below) only 
>>     *"Leaving inner SCF loop after reaching   200 steps" *
>> (200 steps because I set MAX_SCF 200)
>> resulting in a very bad convergence. 
>> As a result, it seems that I have not been running any SGCPMD simulation 
>> but a simple bad BOMD. Am I missing something?
>> How can I correctly set up my input file for SGCPMD?
>>
>> Any help would be greatly appreciated.
>> Thanks.
>>
>> Onofrio
>>
>

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