Hello,
I am trying to run MEP calculation on a simple ethylene oxide molecule.
I tried running it in Forward, Backward as well as default (both) directions
So i start the job from coordinates of optimized TS structure with negative imaginary frequencies and then run MEPGS
For Forward as well default calculations, the GS OPT starts (step0) but after 200 iterations fails to converge...which should be the starting structure (TS already optimized)
For the backward calculation the energy increases and gives me an energy convergence failure...
Since I have ran the same molecule with another software (so I know the IRC works)....I am not sure what part is not working ....please explain and suggest changes
Here is the input
start TS_Eth_h2o2_B3LYP_IRCb
 geo from M06L
geometry units angstroms
C 0.70240430 1.02854192 0.01900758
C 0.42716827 1.85861995 0.04102502
H 1.29500754 0.97410043 0.89356705
H 1.30159049 0.91820617 0.92428135
H 0.92398310 2.14543825 0.88229354
H 0.91822796 2.11267884 0.97925056
O 0.00444306 2.26509742 0.06769202
H 0.23814281 2.41577937 0.85742490
H 0.58224747 0.47936882 0.76067322
O 0.16938925 0.35319650 0.10605228
end
basis
end
Driver
Maxiter 100
end
dft
XC B3LYP
Maxiter 100
grid xfine
end
task dft Freq
freq
reuse TS_Eth_h2o2_B3LYP_IRCb.hess
end
mepgs
maxmep 300
maxiter 200
inhess 2
noxyz
evib 0.0005
stride 0.01
Backward
mswg
end
task dft mepgs
error from forward and default calculations:

Failed to converge in maximum number of steps or available time

Step Energy Delta E Gmax Grms Xrms Xmax Walltime
       
@ 200 230.12944427 3.8D12 0.00053 0.00018 0.00000 0.00000 20803.0
ok ok ok
..................

mepgs: gsopt failed 0

There is an error related to the specified geometry

Error from backward calculation:
Expected decrease in energy 0.000500
Obtained decrease in energy 0.000533

The energy has increased


dft mepgs failed 0

This type of error is most commonly associated with calculations not reaching convergence criteria
All the help is greatly appreciated
Thanks,
Pansy
