Time Dependent Density Functional Theory

The year 2004 was a remarkable one for the growing ?eld of time-dependent density functional theory (TDDFT). Time-dependent density functional theory (TDDFT) is based on a set of ideas and theorems quite distinct from those governing ground-state DFT, but emphasizing similar techniques. Today, the use of TDDFT is rapidly growing in many areas of physics, chemistry and materials sciences where direct solution of the Schrödinger equation is too demanding. This is the first comprehensive, textbook-style introduction to the relevant basics and techniques. The year 2004 was a remarkable one for the growing ?eld of time-dependent density functional theory (TDDFT). Not only did we celebrate the 40th - niversary of the Hohenberg-Kohn paper, which had laid the foundation for ground-state density functional theory (DFT), but it was also the 20th - niversary of the work by Runge and Gross, establishing a ?rm footing for the time-dependent theory. Because the ?eld has grown to such prominence, and has spread to so many areas of science (from materials to biochemistry), we feel that a volume dedicated to TDDFT is most timely. TDDFT is based on a set of ideas and theorems quite distinct from those governingground-stateDFT,butemployingsimilar techniques.Itisfarmore than just applying ground-state DFT to time-dependent problems, as it - volves its own exact theorems and new and di?erent density functionals. Presently,themostpopularapplicationistheextractionofelectronicexcit- state properties, especially transition frequencies. By applying TDDFT after thegroundstateofamoleculehasbeenfound,wecanexploreandunderstand the complexity of its spectrum, thus providing much more information about the species. TDDFT has a especially strong impact in the photochemistry of biological molecules, where the molecules are too large to be handled by t- ditional quantum chemical methods, and are too complex to be understood with simple empirical frontier orbital theory.