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The first SCF step is a disaster

David Shobe
avidshobe@yahoo.com


I am having SCF convergence difficulty (and there aren't even transition metals in my molecule!).  I am new at Firefly, and this is my first attempt to use GUESS=MOREAD.

I copy the first 10 SCF iterations of my output below.  The results (iteration 3 and beyond) vary according to which parameters I have selected in $SCF, but iterations 1 and 2 are always the same no matter what I put in $SCF!  I assume iteration 1 is the wavefunction I read in from GUESS=MOREAD, but why does iteration 2 make that first, disastrous SCF step?  

DIRECT SCF CALCULATION, SCHWRZ=T   FDIFF=T
SCHWARZ INEQUALITY OVERHEAD:     41019 INTEGRALS, CPU TIME=        0.03

                                                                             NONZERO    BLOCKS
ITER EX DEM  TOTAL ENERGY      E CHANGE  DENSITY CHANGE     ORB. GRAD      INTEGRALS   SKIPPED
  1  0  0  -388.903748740  -388.903748740**************   0.000000000       72600037  81761217
  2  1  0  -276.111387353   112.792361387**************   0.869472191       80744208  81131630
  3  2  0  -338.212891275   -62.101503922**************   1.285866356       80778736  81129727
  4  3  0************************************************************       77667278  81352497
  5  4  0************************************************************       81041056  81123783
  6  0  0    64.831233214******************************   1.965860844       81302263  81102913
  7  1  0   104.155503738    39.324270524**************   0.895286223       80819938  81128165
  8  2  0-21382.575588159-21486.731091897****************************       80944456  81124231
  9  3  0   -90.114643710 21292.460944449**************   0.732336451       80833808  81123917
 10  4  0  -185.881527362   -95.766883652**************   3.334914872       80871551  81124031

If it helps, the input file starts as below.  Again, I have tried several options in $SCF, no change in iteration 1 and 2.  The $VEC is taken from a punch file of a HF/DZV(d,p) job at the same geometry.

!
$CONTRL
   SCFTYP=RHF  INTTYP=HONDO ICUT=11 ITOL=30  
   RUNTYP=ENERGY  MPLEVL=4 UNITS=ANGS
$END                            
$SYSTEM TIMLIM=3600 MEMORY=36000000 $END                                          
$SCF    DIRSCF=.True.  $END                                                    
$GUESS  GUESS=MOREAD  NORB=240 EXTRA=.T. $END        
$EXTRAF
   NEXTRA(1)=4,4,4,4,4,4,4,4,4,4                    !DIFFSP for 10 C
   NEXTRA(11)=1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1   !DIFFS  for 18 H
$END                                            
$BASIS  GBASIS=DZV NPFUNC=1 NDFUNC=1 DIFFSP=1 DIFFS=1  $END                                      
$ELMOM  IEMOM=2 WHERE=COMASS $END        
$MP4    SDTQ=.T. $END                                    
$DATA                                                                          
2,2,5,5-tetramethyl-3-hexyne RMP4/DZV(d,p)++//RMP2/DZV(d,p)                                      
DNH 3

C_3         6.0   0.0000000000   0.0000000000  -0.6171527518
C_2         6.0   0.0000000000   0.0000000000  -2.0934695855
C_1A        6.0   1.4521398958   0.0000000000  -2.6001055211
H_1AA       1.0   1.9835899449   0.8863051714  -2.2440032755
H_1AC       1.0   1.4664232611   0.0000000000  -3.6950540786
$END                                                                          
$VEC
1  1-7.05806381E-03-2.34618262E-04 4.28989286E-04 0.00000000E+00 0.00000000E+00
1  2-3.13369076E-04 0.00000000E+00 0.00000000E+00 5.72390159E-04 7.12360225E-06
1  3 7.12360225E-06-1.27864732E-04 0.00000000E+00 0.00000000E+00 0.00000000E+00


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