MRCC
A quantum-chemistry suite implementing high-order coupled-cluster and CI methods, DFT and local-correlation approaches for accurate molecular energies.
Where it fits
Correlated benchmarks and larger-molecule calculations using validated local approximations.
Limits and practical considerations
Local thresholds, excitation rank and interface requirements affect both cost and accuracy.
Licensing and access
Academic registration is free and requires an official institutional email plus a signed licence; other uses require confirmation with the developers.
Official documentation and project