NEB calculates the activation energy or energy barrier?

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dhkim1005
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Joined: Wed Dec 09, 2009 12:48 am

NEB calculates the activation energy or energy barrier?

Post by dhkim1005 »

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.
graeme
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Re: NEB calculates the activation energy or energy barrier?

Post by graeme »

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.
dhkim1005
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Joined: Wed Dec 09, 2009 12:48 am

Re: NEB calculates the activation energy or energy barrier?

Post by dhkim1005 »

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