Hi Jan,
You state on page 12 that MOPAC was faster than GAMESS to converge (despite taking more steps) - was this due to the use of the MOZYME localized molecular orbital (LMO) method?
If not, what effect on the speed and accuracy of MOPAC in your comparison do you think it might have had?
You also state on page 14 the modest increase in speed seen when running the programs across parallel processors. Do you think the "fragmenting" approach of MOZYME ought to assist with this problem?
I thought it interesting that your finding that including three-body dispersion correction had no substantial effect on accuracy as this is also what Li & Muddana found last year. Can you make any guesstimate as to where your PM6-DH3+ method might have placed on their Time vs RMSE comparison graph (they only compare the older PM6-DH+ method)?
Many thanks, Doug