You have increased the allowable iterations for SCF electronic convergence but you need to increase the allowable iterations for geometry optimization. You should also check your transition state solution by running a frequency calculation and looking for a single imaginary frequency. To get a good TS solution you need to make the geometry convergence tighter than default. Your SCF threshold was too loose for this job. Here's an input file that should work better:
charge 0
memory 3000 mb
geometry autosym
S -1.139420 -0.181760 -0.065320
O -0.603930 0.894620 -0.859210
O -0.327300 -1.144590 0.633970
O -2.146750 0.489400 0.987400
O -2.158340 -1.022960 -0.975080
H -2.473210 1.320810 0.584900
H -2.293600 -1.887270 -0.534180
end
basis "ao basis" spherical
* library 6-31G
end
scf
singlet
thresh 1e-4
end
driver
tight
maxiter 999
end
task scf saddle
task scf frequencies
|