Model Systems

Octopus has the unusual feature for DFT codes of being able to handle “model systems,” i.e. ones that have a user-defined arbitrary potential as opposed to a system of real atoms. This can be useful for simplified test calculations or for computations in the “effective mass” or “envelope function” approximation, e.g. for quantum dots or quantum wells. In this series of linked tutorials, we will show how to run 1D and 2D systems, how to set up a user-defined arbitrary potential, and showcase some more unusual features of Octopus. These tutorials assume that you are already familiar with using Octopus. If that is not the case, start first with the Octopus basics tutorials.

• Lesson 1: 1D Harmonic Oscillator   The standard textbook harmonic oscillator in one dimension with two non-interacting electrons.
• Lesson 2: Particle in a box   The classic quantum problem of a particle in a box.
• Lesson 3: 1D Helium   The helium atom in one dimension which also has two electrons.
• Lesson 4: Particle in an octopus   2D systems where the shape of the simulation box is defined by an image file.
• Lesson 5: Kronig-Penney Model   Calculate the bandstructure for Kronig-Penney Model.