Research in the Reiher group is devoted to general theoretical chemistry. The main focus is on the development of theory and algorithms for the calculation of electronic structures based on the first principles of quantum mechanics. The aim of our efforts is to derive quantitative means as well as concepts for understanding chemical processes. All current projects may be grouped according to four main research directions: Relativistic quantum chemistry, bioinorganic and coordination chemistry, theoretical spectroscopy (mainly vibrational spectroscopy), and the description of electron-electron interactions and correlations within wavefunction-based and density-functional methods. One intellectual driving force for our work is the desire to selectively extract relevant (often local) information from a strongly interacting system of particles without introducing arbitrary assumptions on the subsystem.