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Re: Problem with SCF after couple steps of geometry optimization

Solntsev Pasha

OK, i played around and used D5 symmetry for the molecule (i didn't want). It looks like it works. I am trying to use opttol=1d-5 but have some fluctuation.


On Mon Apr 1 '13 6:11am, Solntsev Pasha wrote
>Dear friends.

>I have a problem. I am trying to optimize geometry of ferrocene^(+1) molecule. I use cc-pVDZ basis set for all my calculations. Initially, i optimized geometry of ferrocene+hessian and then used equilibrium geometry to optimize the geometry of ferrocinium cation using UHF wave function MULT=2 icharg=1. I also used $statpt ststep=0.15  $end.

>Then i started new calculation with DFT level of theory BPW91 functional I used converged geometry and MO vectors from the HF job to start the DFT job. I was able to converge the first SCF only with SOSCF=.t. ,  DIIS=.t. didn't work. So, using soscf=.t. i started geometry optimization. However, after two steps of geometry optimization the SCF can't be converged. So far, i used default GDIIS method. But i am not sure what parameters i can use to tune gdiis algorithm.

>I used C1 symmetry for all my calculations. I also wasn't sure do we need to use d5=.t. for the spherical basis set and C1 point group?

>Relevant part of the input file presented below. Any advice?

> inttyp=hondo icut=11 itol=30
> exetyp=run d5=.t. dfttyp=bpw91
> runtyp=optimize scftyp=uhf  
> icharg=1 mult=2 $END
> $SYSTEM TIMLIM=2736 mwords=20  $END
> $zmat auto=.t. dlc=.t. $end
> $SCF FDIFF=.FALSE. dirscf=.t. soscf=.t. diis=.f. nconv=7
> rstrct=.t.  $END
> $guess guess=moread norb=249 $end
> $basis gbasis=cc-pVDZ extfil=.t.  $end
> $statpt opttol=1d-6 nstep=200 hssend=.t. ststep=0.1 $end


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