Diamond band structure

Tight Binding

Introduction There are many methods to calculate band structures of crystals. I implemented the Empirical Pseudopotential project, some of the code can be reused for other methods. One of the methods is simple and fast, the tight binding method, so I simply took the code from the last project, cut a part out and modified … Read moreTight Binding

Ge band structure

Empirical Pseudopotential

Introduction I did not write anything on the blog for a long time. I was very busy, I had less time for it. Nevertheless, I did some work on some projects related with it. One of them, a DFT program that calculates a molecule with the supercell method, was supposed to be the theme for … Read moreEmpirical Pseudopotential

Kohn-Sham equations

Density Functional Theory

Introduction As I already revealed in the last post, I intend to have several projects with Density Functional Theory on this blog. I already have a simple project on GitHub, about a ‘quantum dot’1 with volumetric visualization of orbitals with VTK. I thought that exposing some theory in a separate post would be nice for … Read moreDensity Functional Theory

CO2 molecule

The Hartree-Fock program

Introduction After some posts about the theory it is time to present the Hartree-Fock program1. You might find the previous posts useful, along with the links in there: How to solve a quantum many-body problem, The Hartree-Fock method. Here is the program in action (the final version might have minor differences): Although it doesn’t show … Read moreThe Hartree-Fock program

The Hartree-Fock method

Introduction Last time we ended up with a simplified Hamiltonian: and having the variational principle for help. It turns out that this simplified Hamiltonian is not simple enough. In this post I’ll expose one method that allows one to do calculations for quite complex quantum systems, the Hartree-Fock method. Because the subject is quite large, … Read moreThe Hartree-Fock method