Octopus
A real-space electronic-structure program emphasizing time-dependent DFT, response calculations and electron dynamics in molecules and materials.
Where it fits
Light-driven electron dynamics, optical response and real-space molecular or periodic simulations.
Limits and practical considerations
Grid spacing, simulation boundaries and propagation time steps need separate convergence tests.
Licensing and access
GPL version 3, with separate licence exceptions for bundled external libraries.
Official documentation and project