Infrared Spectroscopy and Hydrogen-Bond Dynamics of Liquid Water from Centroid Molecular Dynamics with an Ab Initio-Based Force Field

A molecular-level description of the unique properties of hydrogen-bond networks is critical for understanding many fundamental physicochemical processes in aqueous environments. In this Article, a novel simulation approach, combining an ab initio-based force field for water with a quantum treatment of the nuclear motion, is applied to investigate hydrogen-bond dynamics in liquid water with a specific focus on the relationship of these dynamics to vibrational spectroscopy. Linear and nonlinear infrared (IR) spectra are calculated for liquid water, HOD in D2O and HOD in H2O, and discussed in the context of the results obtained using other approaches that have been employed in studies of water dynamics. A comparison between the calculated spectra and the available experimental data yields an overall good agreement, indicating the accuracy of the present Simulation approach in describing the properties of liquid water under ambient conditions. Possible improvements on the representation of the underlying water interactions as well as the treatment of the molecular motion at the quantum-mechanical level are also discussed.