Density Functional Theory: Basics and Improvements

This lecture introduces Density Functional Theory (DFT) basics, focusing on the Hohenberg-Kohn theorem and the Kohn-Sham DFT. It covers the challenges of DFT, such as missing dispersion interactions and static correlation errors. The instructor discusses the development of hybrid functionals and the need for more sophisticated functional approximations to correct charge-transfer excitations. The lecture also explores the overestimation of electron flow in DFT calculations and the improvements brought by incorporating atom pairwise dispersion corrections and perturbation theory. Various examples and comparisons with experimental data are provided to illustrate the concepts.