use the empirical correction term of DFT-D3 in the classical MD

[JianBiao]

Dear Marco,
    I mean at each MD step, one can use the DFT-D3 code to calculate the 
gradient and then add them to the values calculated by CP2K. 

p.s. I am sorry I replied to you by email by mistake.

Best regards
JianBiao





在 2014年5月24日星期六UTC+8下午12时13分15秒，Marco写道：
>
> Hello,
>
> In addition to my previous post. Are you trying to add a functional term 
> to the MM force field potential which is similar to the DFT-D3 expression? 
> If so, would the GENPOT (
> http://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/MM/FORCEFIELD/NONBONDED/GENPOT.html) 
> functionality serve your purpose. With GENPOT you can specify a generic 
> potential type. I have not used GENPOT myself yet but I would be interested 
> in any results obtained with GENPOT.
>
> Regards,
> Marco
>
> On Friday, May 23, 2014 11:37:51 PM UTC-4, Marco wrote:
>>
>> Dear JianBiao,
>>
>> Yeah that sounds like a reasonable approach. You are using QM data 
>> derived from DFT-D3 calculations to parameterize a force field of a certain 
>> functional form (presumably employing the Tang-Toennies damping function as 
>> the non-bonded component in addition to bond/angle/dihedral etc. terms). 
>> Your QM data from the DFT-D3 calculations account for dispersion effects 
>> and this should transfer over into your force field parameterization in the 
>> case of a good fit. As you know since you work with parameterization, one 
>> measure of a good fit is whether your parameterized force field 
>> calculations reproduce your QM reference data set and certain properties of 
>> your system. Anthony J. Stone has published a lot of good work in this 
>> field. 
>> (http://www-stone.ch.cam.ac.uk/personal/bibliography.html)
>>
>> What do you mean by add the DFT-D3 to the classical MD parts?
>>
>> Best regards,
>> Marco
>>
>> On Friday, May 23, 2014 9:38:32 PM UTC-4, JianBiao wrote:
>>>
>>> Dear Marco,
>>>     Thank you for your reply. I am sorry I didn't say my question 
>>> clearly. During the force-matching process, one can use the forces 
>>> calculated from the PBE-AIMD as the references, then one can parameterize 
>>> some parameters in the force field such as V(A, B, .. C6=0, C8=0). Because 
>>> PBE fails to describe the dispersion effects, one cannot get the C6 and C8 
>>> from the force-matching. Then during the MD simulation, one can use the 
>>> Grimme's damped empirical correction terms to calculate the dispersion 
>>> parts. So I think this method is reasonable. Could you please give some 
>>> comments? Could someone please help to add the DFT-D3 to the classical MD 
>>> parts?
>>>
>>> Best, JianBiao
>>>    
>>>
>>>
>>>
>>>
>>> 在 2014年5月24日星期六UTC+8上午7时45分00秒，Marco写道：
>>>>
>>>> Hello,
>>>>
>>>> DFT and classical MD are two very different model chemistry's. The 
>>>> parameterizations for BMHFTD (if and when available) and DFT-D3 are 
>>>> completely different. It would be unsound to transfer Grimme's damped 
>>>> empirical correction terms into a classical MD force field in such a 
>>>> straightforward manner. At least I have not seen it done in the literature. 
>>>>
>>>> Regards,
>>>> Marco
>>>>
>>>> On Friday, May 23, 2014 8:23:10 AM UTC-4, JianBiao wrote:
>>>>>
>>>>> Dear CP2K developers,
>>>>>     Is it possible to use DFT-D3 to calculate the dispersion energies 
>>>>> during the classical MD simulations? Because the dispersion term in  
>>>>> CP2K_INPUT <http://manual.cp2k.org/trunk/CP2K_INPUT.html> / FORCE_EVAL<http://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL.html>
>>>>>  / MM <http://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/MM.html> / 
>>>>> FORCEFIELD<http://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/MM/FORCEFIELD.html>
>>>>>  / NONBONDED<http://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/MM/FORCEFIELD/NONBONDED.html>
>>>>> /
>>>>> BMHFTD<http://manual.cp2k.org/trunk/index.html#CP2K_INPUT/FORCE_EVAL/MM/FORCEFIELD/NONBONDED/BMHFTD.html>
>>>>>  is similar to Grimme's damped empirical correction, one can use the 
>>>>> dft-d3 to calculate the dispersion energy and corresponding forces. Could 
>>>>> you please give some suggestions? 
>>>>>
>>>>> Best wishes
>>>>> JianBiao
>>>>>
>>>>
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