Subject: MOPAC 93 open shell calculations

From: [email-masked] (Mike Peterson / Monstergauss)
Date: Sat, 21 Aug 93 15:40:40 -0400

I am trying to verify that MOPAC 93 runs properly on my HP system,
and I can't get an open shell doublet job to run:

AM1 TS 
 alpha, beta-unsat acid from [email-masked] (George Fitzgerald)
 carboxyl radical for decarboxylation (correct answer is 3.19 Kcal)
  C    0.0000000  0      0.000000  0      0.000000  0    0    0    0      0.3262
  O    1.2235372  1      0.000000  0      0.000000  0    1    0    0     -0.2483
  O    1.2372997  1    118.704508  1      0.000000  0    1    2    0     -0.3070
  C    2.1148597  1    157.902093  1   -174.337130  1    1    2    3     -0.0873
  C    1.3006401  1    121.439811  1   -174.074926  1    4    1    3     -0.2313
  H    1.0750946  1     98.120631  1      6.535395  1    4    1    3      0.2176
  H    1.1001354  1    122.939376  1      2.612134  1    5    4    6      0.1720
  H    1.1027606  1    120.905097  1   -178.797410  1    5    4    6      0.1580

I have tried putting "DOUBLET" on the command line, which was used on
MOPAC 6.0 - MOPAC 6.0 doesn't care whether it is given or not (I works
both ways), and neither does MOPAC 93 (fails both ways right after
printing the distance matrix) with:

          HESSIAN CALCULATED NUMERICALLY

          C.I. IS OF SIZE LESS THAN ROOT SPECIFIED
          MODIFY SIZE OF C.I. OR ROOT NUMBER

Any hints/clues appreciated, since it looks like all open shell jobs
will now fail. I have read Section 8.5.8 on the changes in the
C.I. keywords, but DOUBLET states aren't mentioned there.
[I never really used MOPAC 6 open shells, and don't really know
what exactly MOPAC did (or now does) for open shells.]

Mike.