A: Same answer—requires a paid license. However, ORCA runs beautifully on Linux for free.
| Software | Best For | License | Learning Curve | |----------|----------|---------|----------------| | | Transition metals, spectroscopy, open-shell systems | Academic free (non-commercial) | Medium | | NWChem | Scalable DFT, MD, QM/MM, tens of thousands of cores | Open-source (ECL 2.0) | High | | Psi4 | Python-integrated DFT, post-HF, modular | Open-source (LGPL) | Medium | | Quantum ESPRESSO | Periodic systems, solids, surfaces | Open-source (GPL) | High | | GAMESS (US) | General QM, solvation, excited states | Free for academics | Medium | | Dalton | Molecular properties, response theory | Open-source (LGPL) | High |
**Q: Can I get a trial version of