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Harmonic Vibrational Analysis, frequency() and hessian()ΒΆ

  • Psi4 Native Hessian Methods

For further discussion of vibrational and thermochemical analysis, see Sec. Vibrational and Thermochemical Analysis.

frequency() is the only command most users will ever need to access directly to perform frequency calculations. Behind the scenes, frequency() is a light wrapper over hessian() that computes the Hessian then adds a thermochemical analysis.