Hi,
As far as I know, amber DOESN'T handle DFTB3. So please try DFTB2 / SCC-DFTB parameters instead.
Best,
Marc
Sent from my iPhone
> On 3 May 2016, at 08:23 pm, Jacopo Sgrignani <sgrigna.gmail.com> wrote:
>
> Dear all
> I'm new to DFTB and I'm trying to run some QM/MM MD using this level of
> theory for the QM region.
> However, while with Am1/d the calculation run and the geometry of the
> system appears to be reasonable for tens of ps, with DFTB the wavefunction
> does not converge.
> In particular I get this error:
>
>
> QMMM SCC-DFTB: ***************************************************
>
> QMMM SCC-DFTB: ERROR ON EWEVGE (Eigenvalue solver).
>
> QMMM SCC-DFTB: ewevge: ier = 169 inner_scf_count= 70
>
> QMMM SCC-DFTB: ***************************************************
>
>
> QMMM SCC-DFTB: !!!! ============= WARNING ============= !!!!
>
> QMMM SCC-DFTB: Convergence could not be achieved in this step.
>
> QMMM SCC-DFTB: The calculation will continue, but energies and
>
> QMMM SCC-DFTB: forces for this step will not be accurate.
>
> QMMM SCC-DFTB: SCC-DFTB FOR STEP 1 DID NOT CONVERGE AFTER *** cycles.
>
>
>
> I downloaded the ob3 parameters from DFTB.org, however I'm not sure that
> amber can correctly handle DFTB3.
>
>
> Can somebody help me in finding the reasons of this behaviour?
>
>
> thanks
>
>
> Jacopo
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Received on Tue May 03 2016 - 14:00:04 PDT
