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NEB force converge problem

Posted: Wed Apr 26, 2017 6:25 am
by woonghyeonPark
Hello,

i am working on getting TS regarding CO oxidation reaction on metal surface using CI-NEB calculation.
however, after so many steps, image 4, 5 forces doesn't seem to be converged. it fluctuate
I am not sure whether it is structure problem or input problem.

my first try was that
I used 8 images
IBRION = 3
POTIM = 0.01
EDIFFG = -0.1

but the forces didn't converge, after that i switch to this input

IBRION = 1
POTIM = 0.1
EDIFFG = -0.1
and waiting the result

my question is that should i change other tags? or consider other intermediate images?
I attached INCAR, and POSCARs just in case.

Thank you

Sincerely,
WoonghyeonPark

Re: NEB force converge problem

Posted: Wed Apr 26, 2017 4:14 pm
by graeme
First, make sure that all of your frozen atoms are in exactly the same positions in all of your images.

Then, try using IBRION=3 POTIM=0.1 until your forces get to around 0.1 and then you can try switching to (for example) IBRION for faster convergence.