How to generate the torsion, angle and bond parameters

#1

Dear users,

I am trying to generate QM-derived torsion, angle and bond parameters for some molecules but I don’t know whether that is possible with Psi4.
My questions are: can I generate QM-derived torsion, angle and bond parameters for a molecule using Psi4? If yes, how? For instance, can I get the torsion/angle/bond parameters of a molecule with CCSD(T)/aug-cc-pVTZ (method/basis set) or B3LYP/aug-cc-pVDZ ?

Hope that you will help me.

Thanks.

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#2

Not directly out of the box, no.
The typical way is too obtain the Hessian and then fit the QM force constants to an appropriate internal coordinate representation (Seminario method). The Hessian part you can get from PSI4 (numerically for many methods), but the force constant fit needs to be done externally.

Recent work/codes on this can be found, e.g., here:


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