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** problematic SCF convergence **
Masoud Nahali

masoudnahali@gmail.com

Dear Firefly UsersMy system has passed 23 optimization steps and suddenly at 24th step I have encountered a problematic SCF convergence. As I checked there is not any large spin contamination and the spin parameters are SPIN SZ=2.000

and S-SQUARED=6.289. The system contains Ni,C,O, and H and its multiplicity is 5. Below is my input file parameters and attached please find the SCF iterations. I appreciate your help in advance to find the reason and solve the problem.

$CONTRL SCFTYP=UHF RUNTYP=OPTIMIZE DFTTYP=B3LYP ECP=read MAXIT=350 MULT=5

ICHARG=0 COORD=unique d5=.t. NZVAR=366 $END

$SYSTEM TIMLIM=600000 MWORDS=200 $END

$SCF DIRSCF=.TRUE. NCONV=5 $END

$STATPT OPTTOL=0.0001 NSTEP=150 $END

$zmat dlc=.true. auto=.true. NONVDW(1)=123,4,123,9,123,14,123,1,

123,17,123,8,124,4,124,9,124,16,124,6,124,15,124,10 $end

! to activate P2P inteface and DLB:

$P2P P2P=.T. DLB=.T. $END

! to speed up Huckel guess:

$GUESS guess=HUCKEL $END

$smp call64=.t. mkl64=8 load=0 ssg32=0 msu32=0 mkllvl=3 $end

$BASIS gbasis=LANL2DZ extfil=.t. $END

Best Wishes

Masoud

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Masoud Nahali, Sharif University of Technology

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Sat Mar 26 '11 5:26pm

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