Can the Four-Coordinated, Penta-Valent Oxygen in Hydroxide Water Clusters Be Detected through Experimental Vibrational Spectroscopy?

In this study, we construct the hydroxide water cluster, OH<sup>-</sup>(H<sub>2</sub>O)<sub>6</sub>, that (a) could support a stable hydroxide ion with a four-coordinated (pentavalent) hydroxide oxygen and (b) displays hydroxide ion migration. We study the energetic stability and dynamical evolution of the system at different internal temperatures and analyze the corresponding “dynamically averaged” vibrational density of states to discuss the conditions under which the pentavalent oxygen may be observed using vibrational action spectroscopy. We also provide an alternate hydroxide migration mechanism.