The Use of Emission and Resonance Raman Spectroscopy to Examine Structural Changes upon Photoexcitation in Metal Complexes

This chapter discusses the use of emission and resonance Raman spectroscopies to provide insight into excited states within transition metal polypyridyl complexes. The types of excited states present in metal complexes are described, including intra-ligand charge-transfer (ILCT) excited states. Emission spectroscopy is briefly discussed followed by a more in-depth description of the theory of resonance Raman spectroscopy, including sum-over-states and wave packet models. The use of computational methods is described including predictions of resonance Raman spectra. Time-resolved resonance Raman spectroscopy is discussed along with spectroelectrochemistry. A number of examples from the recent literature are provided and then a few specific case studies that use the aforementioned techniques are described to highlight the successes and limitations of these methods, scaling from straightforward analyses to more complex and ambiguous systems.