Octopus is quantum mechanics package aimed at the ab initio virtual experimentation on an ever-increasing range of system types that enables a reliable and accurate simulation of light-induced changes in the physical and chemical properties of complex systems. The first principles real-space-based Octopus project provides an unique framework to describe non-equilibrium phenomena in molecular complexes, low dimensional materials, and extended systems by accounting for electronic, ionic, and photon quantum mechanical effects within a generalized time-dependent density functional theory framework (TDDFT) and beyond. The Octopus package enables the simulation and characterization spatial and time resolved spectroscopies, ultrafast phenomena in molecules and materials, and new emergent states of mater (QED-materials and QED-chemistry).
Octopus is free software, released under the GPL license. It works in parallel using MPI and OpenMP and scales to tens of thousands of processors. It also has support for graphical processing units (GPUs) through OpenCL.