Error in charges increases every OUTER_SCF cycle.
flosch... at gmail.com
Fri May 17 09:10:06 CEST 2013
I doubt that it has to do with the smoothing (as in the posted previously,
I am anyway not a big fan of that option). . I have not tested it yet but
the usual reason for such a behaviour is a badly conditioned overlap
matrix. Means, the inversion of the matrix goes wrong in the preconditioner
and that causes a bad P.
There are various possibilities why that might happen. In your case it
might be your box. 4A is very small. This causes some basis functions to go
over the boundaries of your box. Furthermore you will use many periodic
images (see total number of particle pairs). This might lead to a near
linear dependence in S and so cause problems in the inversion.
In general, as Cp2K does not use k-points it is not a good idea to use such
small unit cells. Using a 2x2x2 box won't be much more expensive and will
give more reasonable results and probably fix your electron problem.
Furthermore you have a very tight convergence criterium here you might even
need a higher cutoff (just tried with 2x2x2, 800 works) to be able to reach
that convergence level.
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