Octopus Features

Octopus does many things in many different ways. This is a summary of what are the features that are currently implemented (some of them are only available in the development version).

Theory

• Density Functional Theory (DFT) for ground-state calculations
  • LDA, GGA, Meta-GGA and OEP functionals available through libxc
• Time-dependent DFT for response
• Independent particle approximation
• DFT+U
• Hartree-Fock and hybrid functionals

Systems

• Works in 1, 2, and 3, and 4 dimensions
• Periodic boundary conditions in 1, 2, or 3 directions

Linear Response

• Through time-propagation
  • Static polarizabilities
  • Absorption spectra (singlet, triplet)
• Mark Casida’s formulation of response
  • Electronic excitations
• Sternheimer (frequency-dependent) linear-response formalism
  • Static and dynamic electric polarizabilities (including resonant response)
  • Static and dynamic electric first hyperpolarizabilities (including resonant response)
  • Static magnetic susceptibilities
  • Vibrational modes

Non-linear response - Dynamics

• Ehrenfest dynamics for the nuclei
• Real-time TDDFT propagation
• Emission spectra, harmonic generation
• Optimal control theory
• Car-Parrinello Molecular Dynamics
• Spin dynamics with collinear and noncollinear spins

Technical

• Norm-conserving pseudopotentials (most commonly used formats)
• Real-space grid discretization (no basis sets)
• Curvilinear coordinates
• Parallelization in domains, states, and k-points.