DFTB with ASE: From Zero to Hero

Maxime Van den Bossche

Learning objectives

Density functional tight-binding (DFTB) is a semi-empirical electronic structure method which can be very useful because of its low computational cost. In this tutorial you will learn about:

  • the basics of DFTB theory,
  • the ASE interfaces to different DFTB calculators (in particular DFTB+,
  • creating a simple DFTB parametrization for silicon using the Hotcent and Tango packages,
  • using DFTB in a global optimization problem (if time allows).

Overview

The tutorial consists of four parts, following the above objectives. The tutorial is provided in the form of jupyter notebooks.

Introduction

  • main approximations with respect to (LCAO-)DFT
  • overview of past applications

Available calculators

  • overview of the different DFTB calculators in ASE
  • practical examples using the DFTB+ code

Parametrization for Si

  • generating electronic parameters using HotCent
  • fitting the two-body repulsion using Tango
  • transferability tests

Global optimization and DFTB

  • example: Si7 clusters using a genetic algorithm

Prerequisites

You need a laptop with a working Python3 environment with ASE 3.18.0 or newer and the latest versions of Hotcent and Tango. To install these packages, run

cd $HOME  # or wherever else you want them to be
git clone https://gitlab.com/mvdb/hotcent.git
git clone https://gitlab.com/mvdb/tango.git
export PYTHONPATH=$PWD/tango:$PWD/hotcent:$PYTHONPATH

References

Further information

Updated: