Dear All
I am doing an NEB calculation for NO dissociation barrier on a metal surface. First, I used IBRION = 3, IOPT=3, POTIM = 0 and TIMESTEP = 0.03, and force converging until 0.1 eV/Å and not going down. Then I increased the TIMESTEP to 0.1 and restarted the calculation but the force is not converging. I also changed IOPT to 2nd order optimizer IOPT= 1 and 2 but still, the force is not stabilizing. Can anyone suggest a solution to the problem? As I already stated, I tried different solutions provided in this forum but had no luck.
I have attached the input I used.
Thank you
Best
Riyaz
Force is not going below 0.1 eV/Å in my NEB calculation
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Force is not going below 0.1 eV/Å in my NEB calculation
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 neb.tar.gz
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Re: Force is not going below 0.1 eV/Å in my NEB calculation
I don't see any OUTCARs  I need them to see what is going on.
Re: Force is not going below 0.1 eV/Å in my NEB calculation
graeme wrote:
> I don't see any OUTCARs  I need them to see what is going on.
Thank you for your response, I have attached the folder with OUTCARs, please have a look.
Thank you for your time.
> I don't see any OUTCARs  I need them to see what is going on.
Thank you for your response, I have attached the folder with OUTCARs, please have a look.
Thank you for your time.
 Attachments

 neb.tar.gz
 (34.63 MiB) Downloaded 769 times
Re: Force is not going below 0.1 eV/Å in my NEB calculation
It's converging  you just have a small timestep of 0.03. You can up to a value of 0.1 and continue the calculation.
Re: Force is not going below 0.1 eV/Å in my NEB calculation
graeme wrote:
> It's converging  you just have a small timestep of 0.03. You can up to a
> value of 0.1 and continue the calculation.
Though I tried timestep 0.1 and the force started to destabilize. But yes I will try again. Another question is, should I rather try a dimer calculation, when the force reaches around 0.1 eV/Ang with CLNEB or continue with CLNEB and converge the force?
Thank you
> It's converging  you just have a small timestep of 0.03. You can up to a
> value of 0.1 and continue the calculation.
Though I tried timestep 0.1 and the force started to destabilize. But yes I will try again. Another question is, should I rather try a dimer calculation, when the force reaches around 0.1 eV/Ang with CLNEB or continue with CLNEB and converge the force?
Thank you
Re: Force is not going below 0.1 eV/Å in my NEB calculation
just get this to converge before you try anything more fancy. And check that you have the same settings in your NEB as compared to the endpoints  I see a disconcerting shift in the entire top layer between the neb images and the final structure.
Re: Force is not going below 0.1 eV/Å in my NEB calculation
graeme wrote:
> just get this to converge before you try anything more fancy. And check
> that you have the same settings in your NEB as compared to the endpoints 
> I see a disconcerting shift in the entire top layer between the neb images
> and the final structure.
Ok..Thanks for the tips and yes I also see a bit of a shift in the surface atoms during optimization.
> just get this to converge before you try anything more fancy. And check
> that you have the same settings in your NEB as compared to the endpoints 
> I see a disconcerting shift in the entire top layer between the neb images
> and the final structure.
Ok..Thanks for the tips and yes I also see a bit of a shift in the surface atoms during optimization.