Theoretical Optical Spectroscopy of Polynuclear Transition Metal and Lanthanoid Complexes

Cooperativity in optical spectra of transition metal complexes is explored via differential many-body expansions. Furthermore, the relation between the fluorescence of Eu(III) complexes and their molecular structure in the gas-phase, as well as the phosphorescence of their chelating ligands are studied and compared to experiment. Dispersion effects are also discussed. Finally, auxiliary basis sets for lanthanides necessary for efficient post Hartree-Fock computations are developed.