NEB calculation of hydride shift step not converging

Vasp transition state theory tools

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NEB calculation of hydride shift step not converging

Post by spbatchu »

Hello Prof. Henkelman and group

I am trying to find the TS of a hydride shift step on Al2O3. Initially, I started a NEB+climb calculation using a single k-point, iopt=3, default time step of 0.1. This calculation showed issues with force convergence; the forces were oscillating between 1 and 0.5 eV/A. To avoid this problem, I lowered the time step to 0.01. Even after trying this, the forces do not converge, and then eventually I see the atoms showing some meaningless movements (C-H bonds dissociating randomly).

I am stuck at this point. It would be of great help if you can provide some suggestions regarding how to troubleshoot this NEB.

Also, I have a question, does the TIMESTEP parameter of an NEB calculation serve the same purpose of POTIM ? Is are the units of TIMESTEP in angstrom?

Attached below is the zipped folder of the NEB with all necessary files. Kindly have a look.
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