Robustness of Frequency, Transition Dipole, and Coupling Maps for Water Vibrational Spectroscopy.

Infrared spectroscopy of the water OH stretch provides a sensitive probe of the local hydrogen-bonding structure and dynamics of water molecules. Previously, we have utilized a mixed quantum/classical model to calculate vibrational spectroscopic observables for bulk water, ice, the liquid/vapor interface, and small water clusters, as well as water interacting with ions and biological molecules. These studies rely on spectroscopic maps that relate the OH stretching frequency and transition dipole to the local environment around a water molecule. Our spectroscopic maps were parametrized based on water clusters taken from bulk water simulations; in this article, we test the robustness of these maps for water in nonbulk-liquid environments. We find that the frequency, transition dipole, and coupling maps work as well for the water surface, ice Ih, and the water hexamer as they do for liquid water. This suggests that these maps may be generally applied to study the vibrational spectroscopy of water in diverse, potentially heterogeneous environments.