[Pw_forum] WFC convergence in NEB calculation

[Nicola Marzari]

Dear Janos,


the only thing that jumps out is the ecutrho - for ultrasoft
I'd go for 8 times the ecutwfc, as a starting point. You mention
that you raised it to 5 times (presumably from 4) - this is still too
little.

Second, try decreasing mixing beta below 0.1 .

A few extra bands (but not remotely 20% more) and some boradening
might indeed help is there are some level-crossing states in the gap.

No other suggestions I could think of.

Out of curiosity, you could try the same identical system, and
converge it using the CP code - either using damped dynamics on
the electrons (very robust, a bit slow) or conjugate-gradients.

			nicola

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Prof Nicola Marzari   Department of Materials Science and Engineering
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