Calculation of harmonic vibrational frequencies. Requires the calculation of Hessian - some interafces provides analytical Hessian, in other cases, the interface numerical_hessian can be used. The analysis can be also run on a precalculated Hessian saved in either previous frequencies job or from a separate Hessian calculation.

Output

Vibrational frequencies and thermodynamic quantities obtained at the rigid rotor - harmonic oscillator level are printed in the output. If the interface provides the derivatives of the dipole moment, IR intensities are printed as well. printing additional information for each vibrational mode is controlled by the keyword freq_print. Additionally, the Hessian is written to a file and all the data inculding normal mode vectors are saved in the Molden format for visualization.

Normal mode scans

The interface can also generate scans along the normal modes. Both one- and multi-dimensionals scans can be prepared easily. The desired grid can be provided by the user or calculated automatically to cover a specified potential energy range in all modes. The generated scans (series of coordinates in .xyz files) can be processed easily by the Scan protocol.