Modelling Dynamics from Stationary Molecular Spectra

Unravelling the mechanisms of energy transfer on a molecular level is one of the central problems of chemical reaction kinetics. Most intriguing from the chemists point of view is the connection between dynamical and structural properties. Although empirically well established this relationship leaves many open questions. Which are its microscopic foundations ? Are there transferable properties of functional groups and how do they determine the course of chemical reactions ?

Modern spectroscopy opens a unique approach to these problems. The key is provided by the interpretation of molecular spectra in terms of explicit quantum-mechanical models of the underlying molecular motion. Studies of OH- and NH2 -groups in different environments demonstrate how experiment and theory combine to draw a detailled picture of the molecular quantum-dynamics. In perfect analogy to the separation of electronic and nuclear motion in the Born-Oppenheimer approximation characteristic motions of individual structural features are adiabatically separated from the overall system dynamics. This phenomenon of vibrational adiabaticity could play a central role in the understanding of the microscopic foundations of empirical structure-reactivity relationships.