This feature allows visualizing vibrations from a “frequency” calculation with quantum chemistry codes (e.g., Gaussian, Q-Chem, etc.)
After opening an output file that has been run with the keyword “freq”, the “Vibrations” toolbar will automatically open.
This toolbar allows you to view the various vibrations of a molecule. Selecting a frequency, and clicking “Start Animation” will begin a vibration.
Avogadro then provides you with the ability to edit the vibration amplitude, it allows you to display the force vectors on the atoms present, and it allows you to adjust the animation speed by the frequency.