I looked in the orca manual but didn't find anything, but in the case of having a molecule adsorbed in a cluster, is it possible to perform the frequency calculation only on the molecule and not on the entire system?

Many Thanks

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    $\begingroup$ +1, but try to add more context to the question. Anyway, have you tried reading Partial Hessian Vibrational Analysis part of the manual? $\endgroup$ Commented Jan 12, 2023 at 9:22

1 Answer 1


Thank you Andrea Pellegrini, the solution for me was to use the partial hess flag with the number of atoms that I want to exclude of the vibrational calculation, like the exemple below, for the 21 first atoms.

partial_hess {0:20} end

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