Hi Dinesh Satpute ,

You should try to calculate the energy differences manually by taking the total energies at 0K. After that, add the gibbs free energy correction to the terms and observe if the error arise from electronic energies or from the thermodynamic correction.

You can also try to extract the xyz structure files and test the reaction with a faster method (xtb - https://github.com/grimme-lab/xtb) and see, if the dimension fit better.

I am not familiar with Jaguar, so I assume the reaction pathway module ( or something alike) checks, if the number of atoms are identical? If not, that can be a reason.

Going a totally different way, try NEB as implemented in orca. This is quite easy to use and can be combined with GFN2-xTB (or GFN1) to obtain exploratory results within a short period of time.

Good luck and regards,

Conrad

Typically, such large discrepancies in energy mean that the composition of the reactants and products is differ. Carefully check the coincidence of the number all types of atoms and electrons in the reactants and products.

Hi,

One thing I have seen once or twice is that transition state searches can be very sensitive to atomic order. Whilst *we* know that e.g. all Pd atoms are indistinguishable, the code does not!

This can cause what looks like a small translation to look like a huge change of structure to the code - which often leads to "total atomisation" as being the best guess for the reaction pathway - obviously nonsense, but it might give energies in the range you are experiencing!

I'm not familiar with your specific code, but I imagine there is a way of plotting the structure associated with that high energy - give that a view in your favourite visualiser (e.g. Jmol or Vesta) and that will be very obvious if it is happening!

Good luck,

Robert

On thing to add, but I don't know how much the influence could be.

You could also have ended up in an electronically excited state like S1 or higher. Combined with the sensitivity with respect to small displacements of the atomic coordinates, this might be worth checking.

Thank you all

As suggested by Alexey, I think the Stoichiometry of reactants could be an issue. Let me check.