use the empirical correction term of DFT-D3 in the classical MD
Marco
synerg... at gmail.com
Mon May 26 03:40:02 UTC 2014
Dear JianBiao,
Sorry I could not be of any help. The DFT-D3 method is implemented in CP2K
(link below):
http://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/DFT/XC/VDW_POTENTIAL/PAIR_POTENTIAL.html#list_TYPE
To perform the type of calculations that you are pursuing, maybe the
following mixed-Hamiltonian functionality could serve your purpose:
CP2K_INPUT / MULTIPLE_FORCE_EVALS
http://manual.cp2k.org/trunk/CP2K_INPUT/MULTIPLE_FORCE_EVALS.html
CP2K_INPUT / FORCE_EVAL / MIXED /
http://manual.cp2k.org/trunk/CP2K_INPUT/FORCE_EVAL/MIXED.html
The following regtest files have examples of mixed Hamiltonian calculations
employing DFT and FIST.
/cp2k/tests/QS/regtest-dft-vdw-corr/ch4-ch4-gpw-vdw.inp
/cp2k/tests/QS/regtest-ot-1/dip-mixed.inp
Best regards,
Marco
On Saturday, May 24, 2014 3:27:12 AM UTC-4, JianBiao wrote:
>
> 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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