[CP2K-user] Is there a proper tutorial on how to use FREE_ENERGY calculations?

Dev Rana dev.... at gmail.com
Thu Nov 12 03:11:23 UTC 2020


Thank you! I think I found a slightly better reference, which might 
interest you and others who may ask this question.

On Wednesday, November 11, 2020 at 1:21:37 PM UTC-5 Marcella Iannuzzi wrote:

>
>
> CP2K, as other codes, can run MD under different conditions, for instance 
> with constraints, restraints, combining different force environments  and 
> so on. 
> The work to extract from the generated trajectories and related properties 
> the free energies is done a posteriori. 
> If you read the literature you can find it out yourself. 
>
> To calculate solvation energies you can follow the work of Cheng et al (
> https://aip.scitation.org/doi/10.1063/1.3250438)
> and following works. 
>
> I cannot say whether you really need the multiple force environment 
> features. Anyway, running simultaneously different environments it uses 
> combined energies and forces and generates only one dynamics. How energies 
> and forces are combined is defined by the user in the input. 
>
> Regards
> Marcella
>
>
> On Wednesday, November 11, 2020 at 4:33:45 PM UTC+1 Dev Rana wrote:
>
>> Thank you Marcella! That is indeed helpful and I will look into further. 
>> However, my question was more about how it's implemented in CP2K and how 
>> the theory (textbooks) can/should be properly run in CP2K's code. For 
>> example, can I just turn the METHOD UI on, set some COLVAR (RMSD solvent 
>> atoms), and expect it to give me Gibbs free energy of solvent?
>>
>> If I want to set a coupling parameter (lambda), I can only set this in 
>> FORCE_EVAL > MIXED > LINEAR > LAMBDA. I can also do this CDFT, but that's 
>> not really what I want. Now if I set LAMBDA in LINEAR to 0.1 or any 
>> d(lambda), do I run a new AIMD using that lambda? I don't really understand 
>> the use of 2 FORCE_EVAL sections, and how CP2K does these calculations. Are 
>> there two sets of output/trajectory files? Or do the two FORCE_EVAL 
>> sections correspond to State A and State B within the definition of free 
>> energy calculations?
>>
>> The two examples on the website are really just an introduction to using 
>> collective variables and metadynamics, not really for obtaining free 
>> energies. (
>> https://www.cp2k.org/exercises:2015_cecam_tutorial:mtd1?s[]=free&s[]=energy 
>> and https://www.cp2k.org/howto:biochem_qmmm?s[]=free&s[]=energy)
>>
>> Sorry, I don't mean to bombard you with questions, however, I'm trying to 
>> learn how to implement the different techniques within CP2K and I'm 
>> struggling with it. It's a lot of guess and test and someone who has 
>> already done this can speed up my (and others who want to use this) 
>> progress. If it's been published or could even provide some technical setup 
>> details that could serve as a basis for computational start point. 
>>
>> Thank you again. I really do appreciate your help! 
>>
>>
>> On Wednesday, November 11, 2020 at 2:53:44 AM UTC-5, Marcella Iannuzzi 
>> wrote:
>>>
>>> Yes many
>>> an example
>>> https://link.springer.com/book/10.1007/978-3-540-38448-9
>>> Marcella
>>>
>>>
>>> On Wednesday, November 11, 2020 at 6:28:08 AM UTC+1 Dev Rana wrote:
>>>
>>>> Hello,
>>>>
>>>> I'm trying to use thermodynamic integration or umbrella sampling to 
>>>> obtain solvation and molecule free energies. Unfortunately, there are no 
>>>> good tutorials in CP2K to do this. Are there good external tutorials or 
>>>> publications that can help to navigate this?
>>>>
>>>> Best Regards,
>>>> Devyesh Rana
>>>>
>>>
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