Mark E. Casida
Professeur, chimie théorique, Laboratoire de Chimie Inorganique REdox (CIRE),
Département de Chimie Moléculare (DCM, UMR CNRS/UGA 5250), Institut de Chimie Moléculaire de Grenoble(ICMG, FR-2607),
Université Grenoble Alpes, 301 rue de la Chimie, CS 40700, 38058 Grenoble
Cedex 9, FRANCE.
Ordinary density-functional theory (DFT) is restricted to calculating the static electronic energy and density of the electronic ground state. Time-dependent (TD) DFT is a parallel formalism which
allows us to extend the power of DFT to treat time-dependent perturbations. Time-dependent response theory then allows us to calculate absorption spectra from TD-DFT and hence to treat excited states. This formalism is explained at the level of a Masters student, first by setting the stage with a reminder of simple wave function theory for excited states as well as some more advanced ab initio quantum chemistry ideas, and then by focusing on TD-DFT. Some illustrative examples are also presented 1,2 . We also direct the interested reader to highly-cited review articles, including our own 3,4 .