[CP2K-user] Compatibility problem of manybody potentials with two-bodies (LJ, Williams) in FIST

[p clabaut]

Hi !

Thanks you a lot for the answer and the idea. I shall check that right away.

Many thanks !
Le dimanche 17 février 2019 17:08:08 UTC+1, Marcella Iannuzzi a écrit :
>
> Hi,
>
> I am not 100% sure but it is possible that the Tersoff potential is not 
> compatible with one non bonding potential.
> You can solve the problem running a multiple force environment 
> calculation, where you define two independent force environments, one for
> Tersoff and one for LJ. The global force should be the simple sum of the 
> two contributions. 
> Please check for reference the examples of multiple force environments 
> that you can find among the cp2k/tests
> Kind regards
> Marcella
>
>
> On Wednesday, February 13, 2019 at 11:05:43 AM UTC+1, p clabaut wrote:
>>
>> Hello,
>>
>> I'm trying to use a manybody potential between a metallic slab and water 
>> molecules in FIST but I would also need to use a simple Lennard-Jones 
>> potential to govern my water/water interactions.
>>
>> Unfortunately, it would seems that the neighbour list building went badly 
>> between those modules because as long as my manybody potential (here, 
>> Tersoff) is present in the input, some of the Oxygen/Oxygen Lennard-Jones 
>> interactions are ignored.
>> Moreover, the verlet_skin parameters starts switching on or off some of 
>> these interactions.
>>
>> For an example, I looked at two couples of water molecules away from my 
>> Pt slab and distant for each other.
>>
>> - When I use 
>>     &NEIGHBOR_LISTS
>>       VERLET_SKIN 0.00
>>     &END
>> with 
>>     &TERSOFF
>>         ATOMS O Pt
>>         RCUT [angstrom] 10
>>      &END TERSOFF
>> and 
>>     &LENNARD-JONES
>>           atoms O O
>>           EPSILON [kcalmol] 0.102
>>           SIGMA [angstrom] 3.188
>>           RCUT 10
>>      &END LENNARD-JONES
>>
>> the oxygens of only one of my water couple are experiencing LJ 
>> interaction from each others while the others doesn'tfeel any forces at all 
>>
>> - When I use 
>>     &NEIGHBOR_LISTS
>>       VERLET_SKIN 1.00
>>     &END
>> with 
>>     &TERSOFF
>>         ATOMS O Pt
>>         RCUT [angstrom] 10
>>      &END TERSOFF
>> and 
>>     &LENNARD-JONES
>>           atoms O O
>>           EPSILON [kcalmol] 0.102
>>           SIGMA [angstrom] 3.188
>>           RCUT 10
>>      &END LENNARD-JONES
>>
>> with no others changes, it is the second water couple that undergoes LJ 
>> interaction but not the first one anymore.
>>
>> - When I use 
>>     &NEIGHBOR_LISTS
>>       VERLET_SKIN 1.00
>>     &END
>> and 
>>     &LENNARD-JONES
>>           atoms O O
>>           EPSILON [kcalmol] 0.102
>>           SIGMA [angstrom] 3.188
>>           RCUT 10
>>      &END LENNARD-JONES
>>
>> with no manybodypotential, both couples are resenting LJ interactions.
>>
>>
>>
>> I have observed the same exact behavior with a Williams potential instead 
>> of a Lennard-Jones. I'm joining the example input in the message.
>>
>> Could you tell me what is going and if it is intended or a bug in the 
>> programm?
>>
>> Thanks you by advance !
>>
>
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