Hi Emmanuel,
I don't believe it's a problem with your input, since it only stopped at
minimization step 1879. However, it clearly indicates that the minimization
procedure is leading to some weird structure. I'd suggest that you try to
print the intermediate structures in the minimization, and take a closer
look at the last ones, when things start to go awry. Sometimes, just
restarting from the last good structure, or giving some atom a small nudge,
can solve the problem.
Gustavo.
On Monday, November 14, 2011, Emmanuel Baribefe Naziga <baribefe.gmail.com>
wrote:
> Hello everyone,
>
> I am having some errors with DFTB calculation and I am hoping to get some
> pointers on how to solve this problem.
>
> My input file is as follows:
>
> DFTB GB minimization
> &cntrl
> imin =1,irest=0,
> maxcyc=10000,ncyc=100,
> ntpr=1,
> ntb=0, cut=999.,
> ntt=0,
> ifqnt=1,
> ntwx = 10,
> igb=1
> /
> &qmmm
> qmmask=':*'
> qm_theory='DFTB',
> tight_p_conv=0,
> scfconv=1.0d-8,
> qmcharge=0,
> printcharges=0,
> dftb_disper=0,
> dftb_chg=0,
> dftb_maxiter=70,
> qmgb=2,
> qmshake=0,
> writepdb=1
> /
>
> I keep getting error messages like:
> NSTEP ENERGY RMS GMAX NAME NUMBER
> 1879 -5.1187E+03 4.9065E-02 2.0210E-01 C2 19
>
> BOND = 0.0000 ANGLE = 0.0000 DIHED =
> 0.0000
> VDWAALS = 0.0000 EEL = 0.0000 EGB =
> -33.5978
> 1-4 VDW = 0.0000 1-4 EEL = 0.0000 RESTRAINT =
> 0.0000
> DFTBESCF= -5085.0779
>
> QMMM SCC-DFTB: ***************************************************
> QMMM SCC-DFTB: ERROR ON EWEVGE (Eigenvalue solver).
> QMMM SCC-DFTB: ewevge: ier = 118 inner_scf_count= 1
> 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: ***************************************************
> QMMM SCC-DFTB: ERROR ON EWEVGE (Eigenvalue solver).
> QMMM SCC-DFTB: ewevge: ier = 118 inner_scf_count= 2
> QMMM SCC-DFTB: ***************************************************
>
>
> which finally ends in NaNs in most cases.
>
> Thanks for your advice.
>
> Emmanuel
> _______________________________________________
> AMBER mailing list
> AMBER.ambermd.org
> http://lists.ambermd.org/mailman/listinfo/amber
>
--
Gustavo Seabra
Professor Adjunto
Departamento de Química Fundamental
Universidade Federal de Pernambuco
Fone: +55-81-2126-7417
_______________________________________________
AMBER mailing list
AMBER.ambermd.org
http://lists.ambermd.org/mailman/listinfo/amber
Received on Tue Nov 15 2011 - 11:00:04 PST
