Spectroscopic properties of transition metal compounds: detailed experiments under variable conditions

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The main research theme of this application is the discovery and detailed characterization of the electronic structure of transition metal compounds and materials built from molecular building blocks containing transition metal centers. This program will provide insight on many fundamental chemical properties and contribute to several areas of modern materials science, focusing on the development of materials with fine-tuned optical, electronic or magnetic properties. It provides a challenging, stimulating training environment for students at all levels, establishing fascinating links between concepts at the heart of chemistry, chemical intuition and quantitative measurements.******We use techniques of coordination chemistry to prepare our target systems and apply a number of optical spectroscopic techniques to obtain insight on their electronic ground and excited states. Recent additions to our instrumentation include setups for variable-pressure measurements and we are currently installing new instrumentation for time-resolved luminescence and transient absorption spectroscopy in the picosecond time range. Experimental spectroscopic results are analyzed with modern theoretical methods, such as the time dependent theory of electronic spectroscopy and electronic structure calculations. Calculated molecular geometries, such as bond lengths and angles, and calculated vibrational frequencies are compared to experimental crystallographic results and vibrational spectra at variable temperature and pressure. The combined spectroscopic theoretical-structural approach will allow us to understand and tune effects ranging from metal-ligand bonding to intermolecular interactions.******We anticipate significant new insight on the quantitative influence of the environment on embedded transition metal compounds through pressure tuning or temperature variation. This information is relevant to the design of sensors or luminescent materials. A key long-range goal of this program is the discovery and understanding of trends through continuous variation of conditions, as opposed to the traditional interpolation of trends from spectra for different compounds, where it is much harder to identify specific physical origins of the observed variations because many properties and parameters are varied simultaneously.