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Atomization energies in partition function for charged systems

Started by w_wonder, February 07, 2023, 08:57:30 PM

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  This is related to
  In RASPA2, if I understand correctly,, A73, including an exponential factor exp(D_e/(kT)).

  If the system includes a charged species, e.g., OH^-, will the atomization energy be calculated from negatively charged atom, e.g., OH^- -> O^- and H?

  From what I understand, the atomization energy is for setting up zero point, as long as the references (e.g., neutral atoms for neutral molecules) are consistent, the calculations should be fine. But, I know very little about the implementation of RASPA2 (go through the source code is quite complicated), does OH^- -> O^- and H OK for simulating charged molecules? Or should I use a different approach?

Thank you very much


David Dubbeldam

In RASPA2 you input the final result: the partition-factor. In more recent RASPA versions the Log of the partition function to avoid over/underflow.
It is an user input, and up to the user to compute it.