Vibrational energy relaxation in water and ice

Hydrogen-bonded systems in the condensed phase are strongly inhomogeneous which makes it impossible to study the microscopic structure and dynamics of these systems with conventional linear spectroscopic techniques. Recent developments in laser technology have made it possible to study the microscopic properties of hydrogen-bonded systems with nonlinear optical techniques like photon-echo and saturation spectroscopy. In this comment we demonstrate the advantages of using nonlinear mid-infrared saturation spectroscopy in studying the vibrational dynamics of liquid water and ice.