Vacancy migration frequency

[Chaure]

Dear users,
If I calculate energy barrier for vacancy migration, How Can one calculate vacancy migration frequency ?
Sincerely

[graeme]

Within the harmonic approximation, you need to calculate the normal mode frequencies at the reactant and saddle point. Then the attempt frequency for hopping is given by: v = Prod v_rs / Prod v_ts , where Prod is the product of all the positive frequencies v = w/2pi, rs is the reactant state and ts is the saddle point.

[Chaure]

Dear Professor,
Is there any link to calculate normal mode frequency at reactant and saddle point?
Sincerely

[graeme]

https://cms.mpi.univie.ac.at/vasp/vasp/ ... ION_6.html

[Chaure]

Dear Professor,
Can we use the INCAR tags to run vibrational frequency like IBRION = 5 or 6 in the same NEB run. Also Do we need to set selective dynamics like calculating mode in one direction like z.
Sincerely

[graeme]

You are able to freeze atoms using the selective dynamics tags. Keep those same setting for the dynamical matrix calculation.