UT theoretical chemistry code forum

Hello.
I wanna calculate the activation energy.
Recently, I studied the activation energy was not equal to energy barrier.
The activation energy indicates the sum of the formation energy and migration energy barrier.
If that is true, which one does NEB calculate the activation energy or migration energy barrier?
Bye.

The NEB gives the migration energy barrier. I'm assuming here that you are talking about the migration of a defect in a crystal. If these defects are populated thermally than you need to determine their equilibrium population from their formation (free) energy. Then, the overall activation energy is the sum of these two energies.

Thank you for your answer.
So, you mean that 'Ea = Ef + Eb', right?
, where Ea = activation energy
Ef = formation energy
Eb = migration energy barrier