# Ab-initio tools for the characterization of nanostructures

The annual ETSF Workshop focuses on topics related to the first-principles description of electronic excitations and spectroscopy of condensed matter, nanostructures, and bio-molecules.

Characterization of materials usually involves the interaction with particles or radiation that brings the system into an excited state. While the ground state, even of very large systems, can usually be well described by density-functional theory (DFT), the calculation of excited states is considerably more involved. Three methods are now well established for excited state calculations:

- Time-dependent density-functional theory (TDDFT).
- Many-body perturbation theory (MBPT), in particular the "GW-approximation" and the "Bethe-Salpeter Equation".
- Quantum chemistry methods (eventually embedded into periodic DFT calculations in order to enable the description of excited states also in a solid state environment.)

These methods have now emerged as the standard for the description of spectroscopy in solids and molecules: e.g., optical absorption, electron-energy loss, angular resolved photoemission, core-hole spectroscopy, luminescence spectroscopy, etc. The meeting will discuss recent advances in both conceptual developments as well as their application to real systems.

## Focus sessions:

- optical spectra of nanotubes, nanowires, bio-molecules, nanocrystals, and other materials of technological interest
- non-adiabatic dynamics within TDDFT
- performance of hybrid functionals for electronic excitations
- electron-correlation effects beyond standard GW, strong correlation
- novel photovoltaic materials
- quantum transport beyond the independent electron approximation
- multiscale computational approaches for excited states