PyDFT

[!NOTE]
Python based Density Functional Theory code for educational purposes. The documentation of PyDFT can be found here.

Purpose

PyDFT is a pure-Python package for performing localized-orbital DFT calculations using Gaussian Type Orbitals. PyDFT currently supports LDA and PBE exchange-correlation functionals. The purpose of PyDFT is mainly to serve as an educational tool to explain the inner workings of a DFT calculation. This program is not intended for professional calculations. It is not particularly fast nor offers a lot of features that more mature open-source of commercial packages offer. It does offer a unique insight into a working code and a considerable effort was made in documenting everything.

[!TIP]
Interested in other educational quantum chemical codes? Have a look at the packages below.

• PyQInt is a hybrid C++/Python (Cython) code for performing Hartree-Fock calculations. This code contains many relevant features, such a geometry optimization, orbital localization and crystal orbital hamilton population analysis.
• HFCXX is a full C++ code for performing Hartree-Fock calculations.
• DFTCXX is a full C++ code for performing Density Functional Theory Calculations.

Features

Numerical integration using Becke grids

Electron-electron interaction terms (both classical as well as exchange-correlation) are performed by means of extensive numerical integration schemes performed over so-called Becke grids. Utilizing these grids, molecular integrals are decomposed into series of weighted atomic integrals.

Molecular orbital visualization

PyDFT can be readily used alongside matplotlib to make figures of molecular orbitals or density fields.

Extensive output

Internal matrices, e.g. overlap or Hamiltonian matrix, are exposed to the user and can be readily visualized using specific matrix visualization routines.

Installation

This code depends on a few other packages. To install this code and its dependencies, run the following one-liner

pip install pydft pyqint pylebedev pytessel

Usage

Check the current version

import pydft
print(pydft.__version__)

Performing a simple calculation

from pydft import MoleculeBuilder, DFT

CO = MoleculeBuilder().get_molecule("CO")
dft = DFT(CO, basis='sto3g')
en = dft.scf(1e-4, verbose=True)
print("Total electronic energy: %f Ht" % en)

Community guidelines

• Contributions to PyDFT are always welcome and appreciated. Before doing so, please first read the CONTRIBUTING guide.
• For reporting issues or problems with the software, you are kindly invited to to open a new issue with the bug label.
• If you seek support in using PyDFT, please open an issue with the question label.
• If you wish to contact the developers, please send an e-mail to ivo@ivofilot.nl.

License

Unless otherwise stated, all code in this repository is provided under the GNU General Public License version 3.