[CP2K-user] Transition State Optimisation using PM6

ma...@gmail.com mario... at gmail.com
Fri Aug 21 15:07:54 UTC 2020

Dear CP2K community,

I encountered a peculiar problem with optimising transition states using 
the semi-empirical method PM6. During the optimisation, the forces acted 
weirdly and the whole structure started flying apart. I should say that 
similar transition states for other molecules have been successful.

I have seen such behaviour before, but in the previous case, the SCF cycle 
failed to converge, which lead to unreasonable forces. In the current case, 
there are no problems with the SCF cycles and as I said, similar transition 
states converge quite quickly.

Furthermore, I should say that I did check the vibrational frequencies and 
the structure is a very good initial guess for the transition state. I 
tried to attach the necessary files (including the geometry optimisation 
frames and the vibrational frequency output), but for some reason, I 
couldn't. If you need the inputs, I can copy them here. The program version 
I am using is CP2K 6.1. If you have any further questions, let me know.

Thank you in advance,
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