Implementing a new Reactive Forcefield

[AsifShah]

Dear Admin,
I am trying to implement a new MoS2 reactive forcefield file into my simulation. The method I use is as follows:

1. I send the configuration to workflow and then choose the forcefield calculator. Then, I choose some inbuilt forcefield and add an optimization block.
2. Then send it to editor with all details present.
3. Then change reactive forcefield parameters with new parameters.

But it shows error. I have attached the python file and as well as the reactive forcefield parameter file. Kindly look into the matter why simulations shows error "Segmentation fault- core dumped"

Thanks
Regards

[AsifShah]

Dear Admin,

Kindly help in this regard.

[Julian Schneider]

Dear Asif,

We will check and get back to you.

[AsifShah]

Dear Admin,
Sure. Looking forward to your response.

[AsifShah]

Dear Admin,
Any update on this?
Here is the actual paper where this ReaxFF was implemented


https://pubs.acs.org/doi/10.1021/acs.jpcc.2c01075#:~:text=Abstract-,We%20present%20a%20new%20Reactive%20Force%20Field%20(ReaxFF)%20parameter%20set,simulations%20of%20Mo%2DS%20structures.&text=2-,structure%20in%20crystallization%20simulations.,unknown%20rock%20salt%20MoS%20structure.

[AsifShah]

Dear admin,
Is there any update on this? I am not able to find a solution.

[AsifShah]

Dear Admin,
Is there any update? It is urgent.

[Anders Blom]

I am trying to be constructive here, not criticize or downplay the problem, but why not fit an MTP for MoS2 instead, if this is urgent (and anyway)? I am sure it will be more accurate and perform similarly.

Even if that takes a week month to fit (which it doesn't, more like a day or two) it's faster than waiting for us to try to debug someone else's potential which may have some mistake in the numerical values, which is almost impossible to sort out; even if we see where the problem is we don't know the correct value. Or if there is a mistake in our ReaxFF model, it will take until September to release a new version...

So in any scenario you are probably much better off fitting a new MTP, and after that you can use the same procedure for any other 2D material (for which there are no ReaxFF potentials).

[AsifShah]

Dear Anders Blom,
Thanks for your response. I thought about it earlier but the problem is that I am not sure how accurate the MTP will be for studying the properties that I want to study. Also, generating AIMD training data for those properties is very time consuming. That's why I wanted to use something that is already tested.

[Anders Blom]

I am sure an MTP can be just as accurate a ReaxFF if not more.

Second, the whole point of the way we fit MTPs is that you do NOT need AIMD data.

If you take a look at the tutorial https://docs.quantumatk.com/tutorials/mtp_basic/mtp_basic.html you can see that we have protocols for automatically generating small sets (100-200) of training structures very fast, based on logical distortions of the unit cell, and for complex systems like amorphous we use active learning (https://docs.quantumatk.com/tutorials/mtp_hfo2/mtp_hfo2.html). In both cases we explicitly avoid AIMD!

[AsifShah]

Dear Anders Blom,
How should one include effects due to electric field?
Is it possible to include optimized trajectories under electric fields?
Moreover, if the MTP is designed in this way, can it predict material distortions when subjected to high electric fields?

[Anders Blom]

MTPs work the same way as for other forcefields in this respect. You need to compute partial charges using e.g. Qeq or even DFT, then use can use those to couple to an electric field. You typically do not include this in the fitting procedure. It might be hard to go to high fields though, but this would hold true also for ReaxFF etc.

[AsifShah]

Dear Anders Blom,

Thanks a lot for your response.

[Anders Blom]

Your original file actually works perfectly well as long as you replace element X with Xe.
Turns out we don't recognize dummy elements like X...

[AsifShah]

Dear Anders Blom,
Thanks a lot.
Yes, now I can run it very well.