Subject: convergence difficulties with GAMESS and PM3 method

From: Connie Chang <[email-masked]>
Date: Tue, 11 Feb 2003 17:32:16 -0500

Hi --

I have a 140 atom molecule and I'm using PM3 on it.  I've used
COOR=UNIQUE and GAMESS seems to correctly reconstruct the molecule based
on the symmetrically unique atoms I give it, but it dies in
convergence.  I have changed the max number of steps to 200 and
increased the time limit to 20 minutes.  On gaussian, a similar system
converged in about 11 minutes.

I've included the relevant part of the log file as well as my input.

Input:
! EXAM23.
!   semiempirical calculation, using the MOPAC/GAMESS combo
!   C140, neutral, RHF wavefunctions
!
 $CONTRL MAXIT=200 SCFTYP=RHF RUNTYP=OPTIMIZE COORD=UNIQUE ICHARG=0
MULT=1 $END
 $SYSTEM TIMLIM=20 MWORDS=150 $END
 $BASIS GBASIS=PM3 $END
 $DATA
C140 test...semiempirical models
Cnh 2

***atom specificiation***

And the output I get:
     NUCLEAR ENERGY =      3040.7430974840
     MAXIT =  200     NPUNCH=    2
     EXTRAP=T  DAMP=F  SHIFT=F  RSTRCT=F  DIIS=F  DEM=F  SOSCF=F
     DENSITY MATRIX CONV=  1.00E-05
     MEMORY REQUIRED FOR RHF STEP=   3178280 WORDS.

 ITER EX DEM    TOTAL ENERGY       E CHANGE  DENSITY CHANGE    DIIS
ERROR
   1  0  0      -76.778068024   -76.778068024   1.257051368
0.000000000
   2  1  0      -38.289475039    38.488592985   1.857634685
0.000000000
   3  2  0      780.350720056   818.640195095   1.999973409
0.000000000
   4  3  0      980.355446048   200.004725992   1.999990110
0.000000000
   5  4  0      843.884948956  -136.470497092   1.999990976
0.000000000
   6  5  0      984.742347206   140.857398250   1.999990976
0.000000000
   7  6  0      843.863672747  -140.878674459   1.999990988
0.000000000
   8  7  0      984.755984770   140.892312023   1.999990988
0.000000000
   9  8  0      843.863529497  -140.892455273   1.999990989
0.000000000
  10  9  0      984.755523393   140.891993896   1.999990989
0.000000000
  11 10  0      843.863499459  -140.892023934   1.999990989
0.000000000
  12 11  0      984.755453179   140.891953721   1.999990989
0.000000000
  13 12  0      843.863493818  -140.891959361   1.999990989
0.000000000
  14  0  0      984.755441308   140.891947489   1.999974020
0.000000000
  15  1  0      169.463522486  -815.291918821   1.999946969
0.000000000
  16  2  0      457.533116772   288.069594285   1.999963404
0.000000000
  17  3  0      603.298480482   145.765363710   1.999989571
0.000000000
  18  4  0      847.510677991   244.212197509   1.999990047
0.000000000
  19  5  0      805.969760494   -41.540917497   1.999991650
0.000000000
  20  6  0      979.330336367   173.360575873   1.999991670
0.000000000
  .......
........
 178  1  0      148.463864386  -839.540700887   1.999959263
0.000000000
 179  2  0      534.479233063   386.015368676   1.999976151
0.000000000
 180  3  0      464.163776551   -70.315456512   1.999990524
0.000000000
 181  0  0      986.773651038   522.609874487   1.999946226
0.000000000
 182  1  0      471.503940149  -515.269710889   1.999905857
0.000000000
 183  2  0      677.038883108   205.534942958   1.999986757
0.000000000

 SCF IS UNCONVERGED, TOO LITTLE TIME LEFT
     TIME TO FORM FOCK OPERATORS=      24.2 SECONDS (       0.1
SEC/ITER)
     TIME TO SOLVE SCF EQUATIONS=    1128.4 SECONDS (       6.2
SEC/ITER)

 FINAL R-PM3 ENERGY IS        0.0000000000 AFTER 183 ITERATIONS

          ------------
          EIGENVECTORS
          ------------
...... END OF RHF CALCULATION ......
 STEP CPU TIME =  1168.46 TOTAL CPU TIME =     1204.0 (   20.1 MIN)
 TOTAL WALL CLOCK TIME=     1318.2 SECONDS, CPU UTILIZATION IS  91.33%
1          ***** FAILURE TO LOCATE STATIONARY POINT, SCF HAS NOT
CONVERGED
     UPDATED HESSIAN, GEOMETRY, AND VECTORS WILL BE PUNCHED FOR RESTART
 EXECUTION OF GAMESS TERMINATED -ABNORMALLY- AT Thu Feb  6 17:01:14 2003

 3179960 WORDS OF DYNAMIC MEMORY USED
 STEP CPU TIME =     0.01 TOTAL CPU TIME =     1204.0 (   20.1 MIN)
 TOTAL WALL CLOCK TIME=     1318.2 SECONDS, CPU UTILIZATION IS  91.33%
 *** ERROR TERMINATION *** IN COMPUTE PROCESS     0
        0 WORDS, CPU=     0.0 SECONDS.

Any thoughts?

Thanks.
Connie