Request for Assistance with CINEB Calculations.

Vasp transition state theory tools

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Achraf
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Joined: Sat Jun 10, 2023 2:01 pm

Request for Assistance with CINEB Calculations.

Post by Achraf »

Dear Professor,

I want to use the CINEB method (VASP) to calculate the adsorption barrier of a thiophene molecule on a Cu (100) stepped surface. I have prepared the initial state where the molecule is located very far from the surface, approximately 9Å (gas phase), and the final state where the molecule is adsorbed in the most stable configuration (complex phase). Additionally, I have used the modemake.pl and nebmake.pl commands to generate intermediate states (5 images). The images were generated perfectly, with the distance between the surface and the molecule decreasing as we progress from the first to the last image.

However, I encountered a problem when I started the CINEB calculations to find the potential energy. The molecules dissociated spontaneously, even when I fixed the positions of the molecules. So I stopped the calculations. Or maybe the molecule's geometry will return to normal at the end of the relaxation?

I have attached a file to this message containing the scripts and the states related to these calculations.

I would be extremely grateful if you could review my question and provide me with a favorable response.

Thank you for your attention, and I look forward to your kind reply.

Yours sincerely,
Attachments
NEB.zip
(469.58 KiB) Downloaded 562 times
graeme
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Re: Request for Assistance with CINEB Calculations.

Post by graeme »

I will need to see a calculation where it has completed at least one NEB geometry optimization - what you posted does not have any forces on the images.

Other problems:

You did not link in our VTST code and so any tags relation to IOPT or LCLIMB will not be considered.

Your molecule has frozen coordinates and so will not relax.

Your cell is changing shape over the NEB path - do not do that unless you really know what you are doing.
Achraf
Posts: 2
Joined: Sat Jun 10, 2023 2:01 pm

Re: Request for Assistance with CINEB Calculations.

Post by Achraf »

I have prepared a new work with 2 images to test the possibility of convergence. In this experiment, I changed some parameters and used only the NEB method, as you mentioned that I cannot use tags related to LCLIMB and IOPT(CINEB). Also, I allowed the molecule to relax spontaneously.

You can find the results in the attached file. Your assistance would be greatly appreciated.

Furthermore, could you please guide me on how to link to the VTST code?
Attachments
NEB 2.zip
(1.66 MiB) Downloaded 583 times
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