"The conversion of dinitrogen (N2) to ammonia (NH3) is of fundamental biological and economic importance. The catalytic conversion is achieved either industrially, using heterogeneous catalysts or biologically, by the nitrogenase enzyme. However, in both cases, the mechanistic details of the process are not fully understood. In order to design advance catalysts that will be essential for a sustainable energy economy, an in-depth understanding of both the biological and chemical mechanisms is required. The goal of this proposal is to develop advanced spectroscopic tools, which will allow for a detailed description of the atomic level processes in the both the biological and the heterogeneous systems. This will include the development of valence to core resonant X-ray emission spectroscopy as a unique probe of transition metal ligation in complex media. High-resolution X-ray absorption, X-ray emission, X-ray magnetic circular dichroism, and nuclear resonant vibrational spectroscopy will be utilized and their chemical information content fully developed. These experiments will be correlated to advanced quantum chemical calculations to obtain a detailed picture of the electronic structure of the catalytic systems. The results should provide a clear understanding of the electronic factors that govern N-N bond cleavage. The proposed research will bring together the fields of biochemistry and heterogeneous catalysis, by utilizing inorganic, physical and theoretical chemistry to advance our fundamental understanding of N2 cleavage. The proposed developments will provide a powerful set of novel tools for the elucidation of transition metal catalyzed homogenous and heterogeneous reaction mechanisms. The long-term goal is to pave the way for rationally designed catalytic systems, based on fundamental mechanistic knowledge."