several maxima & diffusion coefficient

[chub]

Dear all,

I performed NEB calculations and obtained 2 maxima with a miminum in between (see attached). The calculations seem good and it makes sens to me by looking at the diffusion pathway.
I'd like to calculate the diffusion coefficient with the following formula D=D0*ep(-E/kT) with E being the barrier energy for diffusion, which values for E should I use? I believe at the maxima but I'm not sure. I'd appreciate your help and comments.

Best regards
Chub

[graeme]

To first approximation, yes, take the energy difference between the highest barrier and the minimum.

[chub]

Thank you for your help.
Best regards