[gmx-users] force field not found

[Alex]

Yeah, if it is missing bonded parameters, you can always try to find 
something similar, at least with OPLS-AA -- don't really know about the 
other ff.

Alex


On 9/29/2018 8:58 PM, paul buscemi wrote:
> Alex,
>
> I wanted to practice some more with x2top using  a simple CH3 -( CH2)14 -Ch3  pdb model.  oplsaa works fine, but not 54a7 FF generating the erro  “ cannot find forcefield for C “  Th two CH3’s do not cause the error found but the fourteen CH2’s.
>
> In the ffbonded.itp bond angle types i see CH2-S-CH3  , C-CH2-C and  CH2-S_S, but  not C-CH2-C.  Can I add a new atomas ga 5_55   by anology or hunt for the correct parameters  ? (I’ m trying his now )
>    I am assuming the n2t  nor the rtp do not have to be modified since x2top does not rely on the rtp.  This is a fairly basic but essential task, and would surly like to master it.
>
> Thanks,
> Paul
>
>
>
>
>> On Sep 27, 2018, at 5:47 PM, Alex <nedomacho at gmail.com> wrote:
>>
>> Never dealt with TiO2, but the path to parameterizing forcefields for
>> solid-state structures in MD is becoming more and more straightforward,
>> e.g., J. Phys. Chem. C 2017. 121(16): p. 9022-9031.
>>
>> Alex
>>
>> On Thu, Sep 27, 2018 at 4:11 PM paul buscemi <pbuscemi at q.com> wrote:
>>
>>> Alex,
>>>
>>> There are so many important  reactions / applications in which protein
>>> polymer interactions play a role that  the ability  to generate  of
>>> polymers should be part of gromacs repertoire. I’ll keep plugging away on
>>> this and report to the community if I can break the code  - other than
>>> using the very good but terribly expensive commercial programs.   I would
>>> not doubt that many have already accomplished this this task, but it is not
>>> well tracked within this group.
>>>
>>> I might not approach a Molysulfidnitride substrate , ( making turbine
>>> blades ??)  but TiO2 is indeed another surface very popular with proteins.
>>> Most every nitinol surface is essentially TiO2.  If you have some pointers
>>> on that,  I’m listening.
>>>
>>> Thank you again for the assist.
>>>
>>> Regards
>>> Paul
>>>
>>>
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