What Nonlinear IR Experiments Can Tell You about Water that the IR Spectrum Cannot

摘要

Infrared (IR) spectroscopy is a fundamental technique used to explore structural and dynamical details of molecules.It is ideally suited to probe hydrogen bonded systems because the vibrational frequency of a hydrogen bond donor's A-H bond is extremely sensitive to hydrogen bonding with an acceptor B.The shape and position of the hydroxyl stretch mode of water have been used as evidence for the existence of different species of water as well as qualitative depictions of the integrity of the hydrogen bond network.Here,we use nonlinear-IR spectroscopy to investigate the dynamics of four aqueous systems that have very similar absorption spectra.We address the question:to what extent can the dynamics of water vary in systems with very similar absorption spectra?