Vibrational Spectroscopy in the Study of Reaction Mechanism

The detailed investigation of reaction mechanisms is nowadays a requirement in nearly all fields of chemistry. Molecular spectroscopy can provide key pieces of information on the reaction scheme. Among all available techniques, vibrational spectroscopy ones (notably mid- IR absorption, Near-IR absorption, non-resonant Raman scattering, Resonance Raman scattering) represent possibly the most appropriate approaches to get valuable insight on reaction mechanism. In this account/perspective, following the research I have developed so far in different fields (ranging from photochemistry/photobiology to surface chemistry), I will describe the most appropriate vibrational spectroscopy techniques needed to get specific pieces of information. Emphasis will be put on the interplay between the different vibrational spectroscopies, and on the synergy with advanced data analysis techniques, quantum chemistry calculations, and other experimental approaches. After general conclusions, the perspectives in the field of vibrational spectroscopy applied to the study of reaction mechanisms—or, more broadly speaking, to the study of time-evolving systems—will be presented.