Quantum ESPRESSO
An open-source suite for electronic-structure and nanoscale materials modeling based on density-functional theory, plane waves and pseudopotentials.
Where it fits
Periodic ground-state calculations and materials workflows built around a broad ecosystem.
Limits and practical considerations
Validate pseudopotentials, cutoffs and Brillouin-zone sampling; companion programs may need separate setup.
Licensing and access
Open-source suite; follow the licence of each distributed component and pseudopotential dataset.