[ase-users] converging nudged elastic band's in ASE

[Felix Hanke]

Hi all,
I was wondering if there is a generally recommended strategy to converge
Nudged Elastic band calculations within ASE.

I have spent a fair amount of time on the scenarios provided in the
tutorials, but only got the simple Au diffusion on Al(100) to actually
give me a reasonable transition state. The latter I would like to define
as a transition state obtained with climbing images and with a maximal
force (on the transition state image) of, say, less than 0.01 for starters.

I tried a number of things on the dissociation tutorial (N2 on copper),
but did not manage to get anywhere near convergence. Things I have tried
include:
- all relaxation algorithms
- various spring constants
- more images (for better tangent resolution)
(- auto-refinement of the NEB path based on the energy profile)
Not only is there no convergence in the system, but in the end it
actually seems to diverge.
What else can one do?

The attachment contains my latest iteration of the program. Basically
there is a simple running procedure at the bottom, with a few
definitions for NEB and BFGS that clarify the auto-refining procedure
and some additional output. Maybe this helps.

Cheers
Felix





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