Hi,

I would like to estimate the reaction rate constant for water dissociation over nickel surface. I have found the TST and several soft modes after frequency calculations and I am afraid if harmonic oscillator approximation fails in this case. I was wondering if I can use k=(kbT/h)exp(-∆G#/RT) approximation.

If yes, how can I find the entropy of the transition state (one needs the equation: ∆G#=∆H#-T∆S# where ∆H#=Htst-Hreact etc.)? Is the entropy written in OUTCAR? I prefer not to use vibrational frequencies because of soft modes.

If not,does any body know what method I can use?

It would be appreciated if some one could help me.

Regards

Abas

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