Excited States of Semiconductors and Molecules

The investigation of the electronic structure of materials and of electronic excitations forms a major field in condensed-matter physics. The quantum-mechanical ground state of the electrons in the potential of the atomic nuclei plays an important role for the geometric arrangement of matter, for chemical bonding, structural phases, and for crystal and molecular dynamics. Excitations of the ground state are important for spectral properties, like optical spectra, as well as, for transport and particle scattering problems. Excited states and their spectra are commonly used to characterize materials. Furthermore, they are relevant for a large variety of technological applications, like photovoltaics, photochemistry, dye chemicals, light-emitting devices, etc.