Gaussian 03 or 09 may be available free from defunct university mirrors, but they are outdated (no DFT-D3, PCM improvements, or modern functionals). Also, redistributing even old versions may still violate copyright.

That’s it—no license fees, no legal risk.

: Partner with a research group that already owns a license.

Open h2o.xyz in free software like , VMD , or IQmol .