Excitation energies can be measured using various spectroscopic techniques such as UV-Vis spectroscopy, X-ray absorption spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. These techniques allow scientists to determine the energy levels of electrons in a catalyst and how they change during the reaction. Computational methods, such as Density Functional Theory (DFT), are also used to predict excitation energies and understand the electronic structure of catalysts.
