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MEP determination by optimization starting from the TS

Posted: Tue Mar 03, 2015 4:05 pm
by pecher
Dear Graeme and everybody else,
this comment from the "ciNEB barrier plot not smooth" thread caught my attention:

[quote="graeme"]Unless you really care about the path, I suggest continuing with the climbing image until you have a converged saddle. At that point, you can also minimize along each direction from the saddle to trace out the MEP.[/quote]

Does a minimization really yield the MEP? And shouldn't this be dependent on the optimizer? Usually I use Conjugate Gradient and somewhere I've read that the way the optimization is going should be very close to the MEP, but not necessarily exactly it.
But if that is the case, it would mean I can get a much more detailed energy profile compared to NEB where people normally can complain that I skipped something in between the images.

Thank you very much!

Re: MEP determination by optimization starting from the TS

Posted: Tue Mar 03, 2015 7:15 pm
by graeme
This is a very good comment. Aggressive optimizers can certainly move far from a minimum energy path. The best would be a conservative optimizer such as steepest descents with a small time step.

Re: MEP determination by optimization starting from the TS

Posted: Wed Mar 04, 2015 9:48 am
by pecher
Thanks, I will try that out and compare with the NEB interpolation