From chemistry-request@ccl.net Sun Apr 14 13:50:56 1991 Date: Sun, 14 Apr 91 12:59:40 EDT From: Mike Peterson / Monstergauss To: chemistry@ccl.net Subject: MOPAC 6.0 ("new") IRC/DRC validation test Status: R I have been trying to get the "new" MOPAC 6.0 version working on our Apollo system. It is working after a fashion, but the following problems remain: 1) It must still be compiled with 'save' - it fails miserably if the stack is used (at least on the Apollo). 2) On many test cases from the "original" MOPAC 6.0 (and MOPAC 5.0), the ionization potentials differ by several % (e.g. 8.97 vs 9.29 for AlF), and orbital energies differ by up to 1.5 units (this is somewhat shocking). These cases all seem to run for 1 more SCF (1 more geometry?) than with previous versions of the program, and the "new" answers agree in almost all cases with the "new" validation suite output. I find such a difference quite disturbing, and wonder what this means for any existing results based on IP or orbital energies (which seem to be the main results affected). 3) The "acid" test posted here a few months ago (which caused the Cray version of the "original" MOPAC 6.0 to abort, and also caused the "original" MOPAC 6.0 to fail with a segmentation fault on the Apollo) now works just fine Here is the input file to try on your version: AM1 DOUBLET TS alpha, beta-unsat acid carboxyl radical for decarboxylation 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 The correct answer is supposed to be 3.19 KCAL; I get 3.205 Kcal on the Apollo. 4) The 'geometry.dat' validation test works through to the IRC/DRC test: IRC=1 DRC=3.0 T=12.5 DUMP=0.7 KINETIC=10 DRC/IRC STARTING FROM INITIAL GEOMETRY C 0.000000 0 0.000000 0 0.000000 0 0 0 0 -0.0902 H 1.078283 1 0.000000 0 0.000000 0 1 0 0 0.0302 H 1.078224 1 120.066593 1 0.000000 0 1 2 0 0.0301 H 1.078207 1 120.000000 0 180.000000 0 1 2 3 0.0300 0 0.000000 0 0.000000 0 0.000000 0 0 0 0 RESTART DRC=3 T=10 DRC/IRC STARTING FROM INITIAL GEOMETRY C 0.000000 0 0.000000 0 0.000000 0 0 0 0 -0.0902 H 1.078283 1 0.000000 0 0.000000 0 1 0 0 0.0302 H 1.078224 1 120.066593 1 0.000000 0 1 2 0 0.0301 H 1.078207 1 120.000000 0 180.000000 0 1 2 3 0.0300 0 0.000000 0 0.000000 0 0.000000 0 0 0 0 The original output file gives what appears to be the expected output, where there is a table with femtoseconds, etc. The new version just gives the standard vibrational frequency analysis, with no attempt to follow a reaction coordinate. Any clues? Mike. -- Mike Peterson, U/Toronto Department of Chemistry E-mail: mgauss@alchemy.chem.utoronto.ca Tel: (416) 978-7094 Fax: (416) 978-8775