# How do I work with Gaussian in Qiskit?

I am trying to run this Qiskit Nature tutorial (Vibrational Structure) and it uses the GaussianForceDriver. Every time I run the Gaussian job from Qiskit I get this message:

QiskitNatureError: Could not locate Gaussian 16 executable 'g16'. Please check that it is installed correctly.


Do I have to install the commercial version of Gaussian, or should it work with just the Qiskit Nature module? If that's the case, what could be the reason for getting this error if I already installed all requirements for Qiskit Nature? Thank you!

To use the GaussianForcesDirver in Qiskit, you either need an output file generated by Gaussian (such as this .log file from the tutorial). Or you need an installation (and hence also a license) of Gaussian, as stated in the Qiskit documentation here: