[CP2K:1105] SIC does not converge

Fawzi Mohamed fa... at gmx.ch
Thu Jun 12 12:49:53 UTC 2008

On Jun 12, 2008, at 1:50 PM, jschmidt wrote:

> Hi,
> I'm trying to calculate partial charges for an ionic system (Cl and an
> organic cation) and as a first test I tried to find  out what charges
> they have in a dissociated state (distance in my simulation about 10
> Angstroms). Unfortunately I always find a charge of about -0.7 on the
> Cl. My guess is that this might be due to self-interaction and so I
> added the keywords

are you aware that partial charges depend on the method you use to  
calculate them?
Mulliken for example typically underestimate the charge for ionic  
systems (and does not converge wrt. basis set).
Other methods are much better, I also have one that seem to work well  
for ionic systems, but it isn't really ready for public consumption yet.

> &SIC
> to my input (using UKS).

As far as I know you need OT with RKS and rotations for SIC, if you  
really need it probably Joost VandeVondele is the one that knows best  
how to really use it.

> Unfortunately, the wavefunction does not
> converge anymore (at least not after about 500 steps), neither with  
> OT/
> DIIS or OT/CG or OT/SD nor without OT. I also tried different initial
> guesses (atomic, random, restart from calculation without SIC). I have
> the same problems with SIC_METHOD MAURI_US and with SIC_METHOD AD.
> Is there any severe mistake in my settings? Any ideas?
> Thanks for your help!
> Jochen

More information about the CP2K-user mailing list