The efficient conversion of photon energy into electrical charges is a central goal of much research in physics, chemistry, and biology, especially in areas such as photovoltaics, photocatalysis, and photosynthesis.

Ligand and Cluster-size Effects in Metal-mediated Activation of Methane: A Cold Approach to a Hot Problem1) Maria Schlangen and Helmut Schwarz Institut für Chemie der Technischen Universität Berlin, 10623 Berlin, Germany, e-mail: Helmut.Schwarz@mail.chem.tu-berlin.de State-of-the-art gas-phase experiments complemented by DFT and electronic structure calculations of mass-selected, electronic ground-state transition-metal complexes provide insight into fundamental aspects of elementary steps involved in the activation and functionalization of methane at ambient temper